What I've learned refurbishing my 3rd gen wagon (89 GL).
Parts: Hoard them. Buy yourself an ultrasonic cleaner because there's gonna be a lot of greasy used parts you'll need to clean if you intend to run this car for any period of time.
Engine: EA82's are simple to teardown. However, aluminum threads don't like to be abused. Be careful with exhaust flanges and intake manifold bolts. They tend to strip or corrode in some form or another. Pistons, connecting rods, valve springs, valves, valve retainers, oil pumps, OEM water pumps, cylinder heads without deep cracks, oil pickups, and more can be difficult to find. Luckily you're in the right place to find them but still. There's a reason EA82's have gone the way of the dodo. Buying a good parts engine (if you can find one) isn't a bad idea.
Suspension: Front struts and good quality front strut mounts are difficult to find. The chinesium parts that makes up 80% of the parts market for these cars usually aren't worth giving the time of day. Look at DRW Bushings for suspension bushings. I've been very impressed with the bushings and the owner's communication, I'd highly recommend. Springs can be hard to find, there are overload springs out there.
Wheels & Bearings: 4x140 is going to be your biggest hurdle. Looks like you've got a set of shallow wagon wheels (I'm jealous). It's just difficult to find known good wheels, new 4x140 wheels are quite obscure. Bearings aren't too bad if you have a bearing puller. Honestly the seals can put up more of a fight than the bearings. Remember to replace your axle nut spring washers.
Axles: If they're not rusty and crusty, clean them and reboot them. Buy neoprene boots, I recommend EMPI. I use Yamalube ACC-MOLDM-GS-05. Use what you like but it's good grease. You may find out, if you haven't already, that if you do need to replace an axle, it's difficult to buy "the right one". There are multiple different axles (4 or 5, I can't remember) that are used depending on the cars drivetrain and fuel delivery system. Stay away from most cheap axles. Sometimes remans are okay but your best bet is used OEM that have been cleaned and rebooted. Get familiar with the identification bands on the axle shafts near the outer boot and your axle spline count. Outer axle joints cannot be disassembled, to clean wipe the grease off and pour a cleaning solvent into the joint. Pour out the sludge and wipe away the rest. Let the solvent off gas and repack with grease.
Interior: Speedometer cables and throttle cables can be difficult to find. Yes there are cheap parts put there, but those are always a crap shoot. The foam on the HVAC blend doors has probably severely degraded and that will cause issues with actually feeling the full effect of your HVAC system. I'd recommend replacing the foam. Once you've torn the dash off, its easy to do again. Getting it back together can be a pain with the HVAC controls (4 vacuum hoses and a cable). Plastic trim pieces are NLA and will have to be a junkyard, craigslist, or eBay find. If you decide to manual swap the car, get a pedal box from a later GL or a Loyale. Older pedal boxes are prone to cracking.
Glass: Junkyard.
Literature: Get a copy of a parts manual and I'd also recommend a hardcopy of the factory service manual set. Yes you can find them mostly online but having a hardcopy is very helpful.
Good luck :]