Her father had never seen her before I came to him to ask if he wanted to be a part of her life. I think that she should have some one on one time to bond with him before we start bringing in his other family. He has met her for four visits now, a couple hours each time. Three of those visits he brought his son, her half brother, along and all they did was play together while he watched. The last visit with just her dad and her went so well. This time he wants to bring his wife and her daughter, it would be my daughter's step sister. I just don't want to overload her. I want her to have a relationship with her father but I want to take things slow.

Why not a schedule for longer visits, leading up to overnight at his home.

Are there formal custody agreements

I agree. Your daughter will be starting to get confused with all the people she's meeting, she is only 5 after all.

Why don't you just tell her father what you've told us?

I'm sure your daughter will have heaps of time to meet all the others in the months to come. She will remember these first few meetings between her and her father and they should be bonding, just the two of them.

To answer FR Chuck, I try for longer visits but that is all he is willing to spend with her at one time. They live in a two bedroom trailer with the little boy (Tallie's half brother) in one room and the girl (Tallie's step sister) in the other and he and his wife sleep on the couches. When I went there to ask if he would like to get to know his daughter there were dirty dishes all over the place and dog feces on the floor. Not a place I want her to sleep at. I have full and absolute custody because he hasn't been a part of her life until now and that is only because I didn't want her to grow up not knowing who her father was.
To answer Gemini54, I have told her father all this and he says that his wife is being a and insisting on these things, she limits the time he can spend with my daughter by planning other events that he feels he must go to.