Landing crabbed is a normal technique for some big jets ONLY(b737 777 747 and airbuses) They can withdraw the sideload with their side drag struts on the main gears, therefore they dont need the pilot to decrab before touchdown. For boeing this technique is in the manual and recommended on slippery runways, but should be avoided on dry runways with strong crosswinds. The plane is designed to handle a crab touchdown up to the max crosswind anyway.

Sort of. It is because if the wing with the higher "apparent angle of attack" will start to stall, it would then go lower (since it loses lift) which would reduce its angle of attack. Thus it would not be in a stalling configuration anymore, to some extent. Due to the rudder input.

It can spin, but the direction it spins is favorable compared to a skid. Skids cause the plane to roll upside down on spin entry, slips cause wings to roll towards level in a spin entry. But you don't stall and spin in a slip by maintaining your airspeed in the slip (keeping in mind the airspeed may read a bit low due to position error induced by the slip). Very important to rely on pitch/power to control airspeed if/when the ASI becomes unreliable.

you should never be banked that much that close to the ground unless you're well exceeding the crosswind limits.

you land in a side slip. there is no such thing as a "crosswind touchdown slip", you made that up.