I'm confident there are competent attorneys in Dixon. I'd find one for each of you from there. If you're concerned about the abilities of the local lawyers you hire, hire a third "big city" lawyer to assist on the side, while letting the local lawyers be your face in front of the local judge.
Nope. Affidavits are hearsay. With appropriate notice to all the other parties, you can take an evidence deposition of the witness before he or she leaves the country. You can subpoena the witness before leaving the country, which would require the witness to testify at the hearing. You can also ask the court to reschedule the trial.
I could be wrong, but it sounds like you agreed orally to pay your share of the housekeeper. Oral agreements may be harder to prove, but once proven, they're as valid as an agreement written in ink or blood, or carved in stone.
I don't think your housing benefits are at risk. If you maintain a separate bank account to receive your disability income, and use that income for your everyday expenses, you may very well be able to protect most or all of your disability income.