OK, I'll bite.
One word of advice before you start: if you're serious about owing a Land Cruiser and want to maintain it yourself, buy the Factory Service Manual (FSM). You can download a copy here, buy a new/used paper copy (has to be a Toyota branded publication, IMO), or download the whole thing, plus every other piece of information Toyota published at TIS (a 2-day subscription is all you need):
For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.
https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&contextType=external&username=string&password=secure_string&challenge_url=https://techinfo.toyota.com/techInfoPortal/login/techinfo&request_id=6841849349380041924&authn_try_count=0&locale=en_US&resource_url=https%3A%2F%2Ftechinfo.toyota.com%2F
These trucks aren't complicated, mostly, and are very reliable. You can pay anywhere from $1000 to $25,000; what you pay is entirely up to you. I've owned every model, except the FJ55, and this one has been my favorite since it was introduced.
A. Maybe, probably. I described the entire system for you. So did
@Rifleman.
B. Maybe. Can't tell from here. Usually it's low refrigerant that is the problem. Could be a belt. (loose or missing)
C. Don't know what you're asking. Land Cruisers have engine coolant based heating systems. If the cooling system integrity is good, the heater should work. Hot water is cycled through the heater core, behind the dash, and a fan blows air across it. That's all there is to it. If the cooling system is OK and the heater doesn't work, the valve needs to be replaced. It's on the center of the firewall, in the engine bay; takes 10 minutes.
(immediately above the blue topped part in the photo)
D. Yes. Yes. No.
E. Big black tube; runs from the air cleaner to the throttle body. Yes. Yes; don't know.
(looks kind of brown here, but it's black)
View attachment 1643565
F. Yes, but you have to remove the head. If there is coolant in the oil, the head gasket is definitely leaking. I've never worried about it.
G. Yes. Do it yourself, the tools are $30. Take pictures and save yourself the cost of pen and paper.
View attachment 1643568
H. No. One of my 80s has 260k on it. The shocks are gone (they're the originals), and I can jump up and down all I want. The chassis never bounces. You can drive it and tell the ride is not as smooth as it was when it was new.
I. The VIN label, on the driver's door describes the options. The next to last line (on one of mine) looks like this:
View attachment 1643572
C/TR: color/trim
045 = white, FN41 = brown fabric seats and door panel inserts (LB41 is brown leather)
A/TM: axle/transmission
K292 = open differentials, front and rear (K294 would be electrically locked differentials)
A343F = transmission model code (4-speed automatic)
FZJ80L-GNPEKA: frame type (US spec with lift up rear door and tailgate)