I am in need of sound, truthful and solid advice.

My husband & I have had custody of our grandson for a over a year. (Note; last year, we were hoping that reuniting them would help resolves some issue so he lived with her and the boyfriend from Feb-May of 08. She moved in with us in May 08 for 3 weeks and then left our home while Nathaniel was with his step dad for the day. She refused to wait 2 hours until his return to leave and left without him. ) She gave birth to another child this past October. (fool! I have seen the child but feel sorry for the life he is going to live and there is no way we're taking on another child, especially since we do not get along with that father) She currently lives with the new baby’s father but her wants her out of his home ASAP and she has nowhere to go. Living with us is not an option.
Nathaniel will be 7 next month and trust me he is smart as a whip. Nathaniel does not ask about his mom, if he can call or see her and expresses he does not want to live with her. We have thoroughly explained what adoption is to him and he clearly understands what that means (we even waited a week to bring it up to him again and he was able to tell us exactly what adoption means and clearly wants us to adopt him. He told his mother (via phone) on Christmas day that he wants to live here, not with her and for us to be his forever parents.
Mom's history is very troubled... she has been charged with numerous counts of theft (from employer, by check, by credit card, identity theft) and served a month in prison. She has at least 4 charges that we know of. She continues to steal as she revealed to me in Oct 08 she just got charged again this summer for theft. (yet all she gets is time added to her probation~how messed up is that? ) In the past she boyfriend hopped while living with us & hooked up with the current BF have a place to live while divorcing her ex-husband. The boyfriend she is with now wants her out of his house ASAP and custody of the new baby. He also does not like Nathaniel and is glad he's gone.
Before we got custody he we have witnessed abuse while they both were in our presence both before & after we got custody. (She and Natty lived with us until he was 2 1/2.) For example, she needed a ride somewhere and she and Natty were in the backseat. He wouldn't be quiet and she was getting angry and as I turned to speak to her, I saw her slap him in the face as I turned toward the backseat. This left a red mark but unfortunately we did not have a camera with us to evidence this. The slap was loud enough to be heard by both my husband and myself while the radio was on a low volume. Over the course of his lifetime, I have heard her screaming at him about his behavior, telling him she’s going to throw him against a wall, beat him & give him away if he doesn't behave and what a horrible little boy he was.. Both she and Nathaniel have told my husband & me that the boyfriend pinned him down while she spanked him. They both told me that the BF has punished & spanked him excessively. She has told him she wishes she never had him. Those comments were made while on the phone from Feb-May of 08 to us asking US how to control HER child) When she had custody of him for 3 months, she called us several times a week asking how to control him. Nathaniel has told us that she repeatedly told him she wishes she never had him. She has also told him she was going to put him out with the trash when he misbehaves. (We heard her state these things while talking on the phone with me or her father.)
She is a horrible housekeeper. When I had to pick up his clothing & personal belongings while mom was in prison, the house was fitly and stank of urine. Everything had to be washed in an enzyme detergent to get rid of the odors and most personal belonging had to be thrown out. The bedrooms & bathrooms were pigsties, dirty dishes piled up and sitting for who knows how long with visible mold in the kitchen and bathroom areas and the house reeked of garbage, urine and filth. Dirty laundry was piled up everywhere. (Why didn’t I think to take my camera! That would’ve helped a lot), The entire house was probably never cleaned by the amount of filth. Marina's housekeeping skills in the past, both while living with us and in her homes were filthy, which we witnessed when visiting her and Nathaniel. Nathaniel has a history of bed wetting and his bedroom & the supposedly “clean” clothing & personal belonging that I picked up in Oct 07 reeked of urine. The bedding was visibly urine stained and stank horribly. The baths looked & smelled like a dirty public restroom. He told us that his mom told him she didn't have the money for Pull-Ups so he rarely wore anything to absorb the urine. Nathaniel also told us that many nights they ate cereal for dinner & there was never much food in the house because mom didn’t use food stamps for food.
Nathaniel has ADHD. She did have him tested for ADHD by a pysch, had an action plan but never kept the first counseling appointment, which is confirmed in writing by the therapists records nor kept him on medication recommended by the pediatrician. (He was briefly placed on medication but discontinued it as evidenced in his medical records but discontinued when mom felt the meds weren't working. No other ADHD/mood modifying medications meds were tried until he was once again in our custody We have had him in counseling & on med's since Sept 08 and he is totally different child than when we first got him in Oct 07. He was very unhappy, withdrawn, rebellious, depressed, angry and sad etc.
The child has been through so much and yet with our assistance, medication and therapy, has totally turned around his behaviors and attitudes. He is a delightful little boy, always loving, he loves doing his school work and learning new things, he is eager to help with things, such as taking dinner dishes to the sink, helping fold laundry & simple tasks. When we first got custody of Nathaniel in Oct 08, he was not completing his schoolwork, was not able to recite the entire alphabet in order & confused most of the letters and was not able to count to 20. He didn't know he needed to wipe his bottom after a BM, give himself a bath or brush his teeth.
Despite the fact that he is 6 and many 6 year olds tend to stretch the truth (will be 7 on Feb 8th), his statements to us confirming this information have always been consistent with no variation in relating events and occurrences.

She lives on welfare (which she is about to lose for not reporting her home status of living with BF and his income), cannot get a job due to criminal history. Marina has always had mental health issues and told me several times, both presently and in the 11 years that I have know her, that she does not take her medication at all and/or as directed.

We had a custody hearing in November at which time the judge ordered her to get counseling, a job, health ins for Nathaniel and an apartment with at least 2 bedrooms. She has done none of these things. We have another custody hearing in Feb. to determine who get custody. Marina has consented to allow us to adopt but only if it's an open adoption. So my questions are:

1. Is she considered unfit??
2. If she changes her mind about signing the adoption papers before the court hearing do we still proceed with the hearing as evidence to prove her unfit?
3. If we set specific terms for an open adoption, such as having a one day visit (at my home!) on a birthday, Christmas, etc and Nathaniel doesn't want to see her, what happens then? Do we have to force him to see her?
4. Per PA open adoption laws, what are her rights once the adoption has gone through?
5. What happens if she backs out before signing the adoption papers?
6. Per PA law, can she change her mind within a certain time frame? (Although with armed with all of the above evidence I can’t imagine a judge giving her custody again)

I will talk with my attorney tomorrow but am hoping for valid answers to ease my anxiety and am trying to get a sense of this whole process. I have net searched PA laws, but have found very little about a mother's rights during an open adoption process and after the adoption.

I am very grateful for your advice. Thank you.