Hey Keith, welcome to the club hehe
The AX-15 is fine, I've seen em behind 350s. (wouldn't recommend that though)
But if its a 4-banger, it should have the
AX-5, which isn't quite as good.
But behind a 4cyl, you should have no problems.
The axles are fine, unless you go to 35s and
low gears and lockers. (Even then they are ok if they aren't overly abused, just carry some spare parts)
The Dana 30 is a good axle, and with a shaft upgrade and truss is a capable axle. The Tri-County gear YJ runs a Dana 30 front in the RockCrawling Championships and does very well.
As for the 35C rearend, it's a bit weaker. I'm about to swap mine out for a Ford 8.8" hopefully next month
The X-fer case is good, particularly with an SYE conversion and the new 4:1 ratio kit, and the 4-banger is a good engine if you don't mind the smaller output.
I hope that helps a bit, if you need more help or more specific/detailed info. PM me or visit my website and shoot me an email.
You'll have to send me some pics for my site when you get your jeep