Okay, so I'm renovating my bathroom and running into some issues with the old plumbing.

Here is a link to some pictures of the situation which will do a much better job at describing things than I can.

Picasa Web Albums - Jonathan - plumbing

Obviously the ideal situation would be to replace the lead with PVC. How easy is this? Can it be replaced at the hub or would I have to rip out the entire floor and replace the bath drain as well? I don't want to rip out any more of the floor than I have to.

The other option, as I see it, is to buildup the floor to the old tile with plywood and add another brass closet flange. Is this recommended? Have I destroyed the top of the lead pipe to a point where this is no longer possible? I think it can be hammered back into place but there is at least one small hole in the lip since I was not as careful as I should have been when removing the old brass flange.

If I use the old lead pipe and a new brass flange, is there anything I should keep in mind when attaching the two? Should I hammer it into place and use solder or some epoxy as well? Once I do all this, the flange will probably sit about 1/4 inch below the new tile. Will this be a problem?

Any advice would be appreciated.

I don't have to tell you the correct thing to do. You already realize it's best to replace the closet bend with cast iron or PVC. I'd opt for PVC.
This can be done by removing the lead closet bend and installing a PVC closet bend, ( you could substitute a short piece of PVC with a quarter bend and a raiser if a regular PVC closet bend isn't long enough).
Now, how to make a lead and okum joint between the cast iron hub without burning the PVC with molten lead? No problem! You simply yarn and pack in the oakum in the usual way but instead of pouring a lead joint you pack it with lead wool and caulk it just like a poured joint.
Your next question will be, " Will this lead wool be as water tight as a poured lead." The answer to that is that the lead doesn't hold water. The okum, (after it swells) makes the joint water tight. All the lead does is to secure the oakum and keeps it in place. So go aqhead and change out that old lead closet bend and good luck, Tom

Thanks for the quick reply. So I can replace just the closet bend where the lead meets the cast iron? And this can be done without ripping up the rest of the floor? I agree that PVC is the best way to go but I might be in over my head on this one. Assuming I hire a professional, do you have any idea of how long the job may take?

If the guy you hire's any good he will remove the old lead and okum joint and lead loset bend in a hour or so. If he has a working knowledge of poured lead and okum joints he will be able to pour a lead joint without burning through the pvc. If he's not familiar with the process then he can use lead wool in place of molted lead. I would advise waiting until you replace the floor until setting the closet flange. The entire job shouldn't take over three hours unless he runs into difficulties that are unforeseen. Good luck, Tom