Redford

Unless you have a complicated case, hiring a lawyer won't speed up or increase the chance for approval. The facts are the facts, and the long processing times are long processing times.
 
Whether or not you should get a lawyer, I'd highly suggest looking at the guides here, reading the instructions, then asking questions. If you still aren't getting it, then consider professional help. Even if you do get professional help, you still need to be on top of everything in the process...there is no set it and forget it.

If you have a fairly simple case then a lawyer will not help at all. I only did a lawyer for my wife's K1 was because I was in Afghanistan working at the time. But I did AOS and ROC all.by myself and VJ. 

The father would file an I-864 as a joint sponsor. The I-864A for him would not apply as he is not in the same residence as your wife.
 
If her father files taxes jointly with his spouse, then his spouse would file an I-864A as well. This is not strictly required, but is usually requested so it should be provided to avoid an NVC checklist or 221(g).