First, the Warn hubs: Advance Auto Parts can order them for you. They should cost about $150 or so. Any competent mechanic can install them in less than an hour. Note: you didn't say what year your Sportage is. If it's a 2002 Warn will say they won't fit. That is incorrect. They WILL fit.

Having the hub vacuum diagram won't help you. The vacuum system IS the reason the hubs don't work. No amount for "fixing" or modifications will fix it permanently. Manual hubs and disabling the vacuum system is the only good repair.

Gas fumes in the heat: The rubber hoses around the fuel pressure regulator are cracked. Again, a competent mechanic can fix that in about 10 minutes. That regulator is on the front of the fuel rail with the injectors. Show him this thread.

High idle: Known problem. Caused by corrosion on the electrical connectors to several sensors. If you do a search in Kia Tech you'll find the repair for this.

Once you fix the above assorted problems then go after the check engine light. Autozone will read codes for free.

1998 Sportage - Gone.
2004 Honda Civic Coupe.
2007 Suzuki Grand Vitara - She got it.