Incest Survivors Support Group
Incest refers to any sexual activity between closely related persons that is illegal or socially taboo. Consensual adult incest is very rare. Incest between adults and prepubescent or adolescent children is a form of child sexual abuse that has been shown to be one of the most extreme forms of childhood trauma. If you or a loved one is a survivor of incest, join the group...

I think you need to talk honestly to your Aunt and Uncle about your absolutely justified concerns regarding your other uncle and your kids. Even if he hadn't attacked you he is a convicted sex offender.
See if you can come up with some arrangement whereby you can see them without your uncle being around - can they come over to you? can you meet outside the home? how about when your other uncle is away?
we never stay over night in their house, always in a hotel. we did camp in the back yard one time, my hubby is allergic to pets. I always went with my kids when they had to go to the bathroom. let's call the uncle who attacked me Chuck. Chuck usually retreats when we are visiting and is usually working or in his room, but he was more "in your face" this time. we were telling ghost stories by the firepit and he actually stood behind my son and started saying, "there's a monster back here." I was furious and got my kids to go color in the tent. I cannot believe how cruel he was.I don't think he was just being "retarded", he was taunting me. I think he wants me to know that this is his turf and he is tired of me visiting.
Do you actually love them for who they are (not because of the gifts or because you want to love someone in your family so you can feel you belong and have a family)?
Meet them away from him, away from the house.