Welcome!

I have an Orange RX R620 receiver with a DX5e and it's great when it works. When it works being the key thing, as it can be a temperamental so-and-so... If you can get something a bit more reliable, definitely do - it'll save you plenty of time troubleshooting.

The parts list you've posted would be a solid start too, most people start out as 'drill bricks'. Battery should be fine, rule of thumb with overvolting is no more than 1.5x the voltage (4S lipo is 14.4v, so you're fine there). In all honesty, if you upped your battery capacity a little (maybe 3000-3500mAh) you could double up on the drills and have a 4wd pusher if that's a way you wanted to go. Tormenta 2 used 4x 550 drill motors and that had plenty of push behind it... The TZ85s are great little things too, used them in all my combat machines and never blown one yet even after taking plenty of stalled motors. I have broken two but that's because spinners happened, and are the reason we can't have nice things... (one was fixed in the end pretty easily though)

Also worth a mention, ranglebox.com stock M6 threaded bar which would be really useful for construction, even more so if you don't have a wealth of tools available! If you want to go for a decent chassis material too, look for 15-20mm HDPE, directplastics.co.uk sell that, it's great stuff, easy to work with and can take a lot of punishment. That, and it's relatively cheap.