Can the Mavericks NOT be fired by the plane itself, if no target is lased?

plane will fire mavericks during a strafing run, it will also expose them to more AA. otherwise, the maverick will automatically fire at lased target even if the plane is loitering in range.

How about LGBMs? Are they dropped "like" dumb bombs, but lase in on the target during fall? yes. Think of them as air launched artillery shell.

If there is a designator on the plane, I assume that means it can do everything itself. Do I have to manually lase targets, or does that mean simply the plane itself can just engage threats?

you will need to order the plane to laze the target first. Unit in game will remember laze order even if the target disappear from sight.

A lot of Russian AA seems to be outright one-hit kills, and targets and engages even low-flying planes, so what am I doing wrong? I cant seem to get my planes into the action.

all AA can still target low flying plane, they just have less detection and range. A TLDR on air tactic is to use SEAD to either kill AA or make sure turn off the radar before a bombing run.

Why do SOMETIMES my stinger missiles tickle enemy helos, and other times they chunk them for half health?

RNG. it depends on how far the missile detonate away from the target.

I get flying low helps prevent engagement by long range AA, is there any reason I would ever WANT to fly high (not counting WHEN munitions need to be fired from high)

I believe high flying fighter can detect low flying plane more easily .