I have a bathroom project I am working on and as I understand I can have minor drains come into the main one as long as they are vented. Is this correct?

The way the bathroom ended up being laid out the toilet is the farthest from the point where the stub comes up out of the concrete in the basement. In order for it to get there it will run north between the joist for 14 feet then turn down 9 inches to get under the joist and then make a 90 degree turn to the east and run 9 feet. From there it will turn back north 90 for a foot and then turn down drop 8 feet to the stub coming out of the slab. Are there too many turns?

Also this bathroom is an addition to my house that is only one story but it is directly next to the two-story portion there are windows that open to a second floor bedroom is it OK to vent out this roof?

I have a bathroom project I am working on and as I understand I can have minor drains come into the main one as long as they are vented. Is this correct?

The way the bathroom ended up being laid out the toilet is the farthest from the point where the stub comes up out of the concrete in the basement. In order for it to get there it will run north between the joist for 14 feet then turn down 9 inches to get under the joist and then make a 90 degree turn to the east and run 9 feet. From there it will turn back north 90 for a foot and then turn down drop 8 feet to the stub coming out of the slab. Are there too many turns?

Also this bathroom is an addition to my house that is only one story but it is directly next to the two-story portion there are windows that open to a second floor bedroom is it ok to vent out this roof?

You have me a little confused. Your heading says lavatory but your post says toilet. It doesn't make much difference which one it is. With that many bends I would install a least two cleanout tees because with that many bends and doglegs you're going to need them. Would it be possible to straighten the run out a tad?
You ask," I can have minor drains come into the main one as long as they are vented. Is this correct?"
That's correct.
"Also this bathroom is an addition to my house that is only one story but it is directly next to the two-story portion there are windows that open to a second floor bedroom is it ok to vent out this roof?"
Section 1494.4 and 5 Chapter 14 0f The Standard Plumbing Code says that NO vent terminal shall be located directly beneath any door, window or other ventilating opening of the building. Also no vent shall be within 10 feet horizontally of any such opening unless it's at least 2 feet above the top of such opening. In addition you MAY NOT terminate a vent under the overhang of the building.
That's what the book says. Good luck, Tom

Thank you for the reply I have decided to forget worrying about the pipe running across the room and do as you said Straighten it out a bit. It will now drop down right from the toilet and the sink will join in during this drop of 18 inches which is what it will take to get the 3 inch drain pipe under a beam that runs threw the center of that room. Then run it at a angle facing North East 16 feet to where the 3 inch stub comes up out of the floor and then just turn it down to the stub. This sound like a better solution?

Thank you for the reply I have decided to forget worrying about the pipe running across the room and do as you said Straighten it out a bit. It will now drop down right from the toilet and the sink will join in during this drop of 18 inches which is what it will take to get the 3 inch drain pipe under a beam that runs threw the center of that room. Then run it at a angle facing North East 16 feet to where the 3 inch stub comes up out of the floor and then just turn it down to the stub. This sound like a better solution?

Anything's better then the way you had it set up. If you can why not install a cleanout at the bottom of the 18" drop. It may save you the hassle of pulling the toilet if you have to snake the line. Good luck, Tom