Paulette....first off it will take time!
This that I am posting is from what I have learned/experienced in that last month. (Mimi has been with us for a month now~~and she was 13 months when we got her)
1) I really think that Jockey will warm up to Derby within the next week or so. (With us just getting Mimi a month ago.~~She didn't want to play with Moose for the first few days. She would run to me too.) It took about a week before she would actually play with Moose.
2) Mimi came to us "pee pad" trained.
Well she thinks the "carpet" is a huge pee pad!
She is getting better now...but I am on her every hour to go outside to potty! If she leaves my side (which is only when she goes to sniff............then its outside to potty~ Is it possible to have her confined to the bathroom (or where there is no carpet or hardwood floor) and have Derby as you normally do? I do know it is hard to have them separated but maybe for a bit it would be best. Maybe you could put a large blanket under the x-pen so it won't scratch your floor.
3) Barking? I still think he is feeling a little unsecure. I think the "positive" training is good.
4) Not sure about crate training...we have never done that.