Hell, since your Dad can make them have him make a set of each, then you have that many more options. But I do agree with Smaxxin, maxx size rims and tires will probably look better with that wheel base.
The good thing about the TLT axles is that everything inside is metal, but like everything else they will eventually break. IMO because it will be geared down it should be ok. I ran some Imex mt's on my and never had problems, at 5" tall they were the biggest 2.2 available.
The pede tranny is an excellent choice, I suggest you get an aluminum idler gear, and steel yokes for it. When I ran a high powered pede I always used HPI 48p spur gears, they held up better than any other brand out there...including Robinson Racing. The lowest you can gear it is 12/93.
I was worried about axles because I had posted the same question on another site, and everyone said itd be really touch on the axles. I asked even if they were narrowed and they said the force from the height would be the stresser on the axles.. But then I was looking and they sell adapters for Maxx size rims and tires for a Tlt so it can't be to bad, right?
One of our guys in our club is a avid crawler and he is a very nice gent, if you ever get over to the www.lsrcc.com site his sign on is silverdirt, we do not have any crawler activities in our club but that guy might be able to help you out, I race with him and usually either pit with or real close to him and he will help where he can, I can not say how knoledable he is but I am sure anything he can help you with he will.