It has been a few years since I had the engine out on my car... Read up on engine removal guides and have a question.

Why do I have to remove the fan, drivebelts, loosen alternator, ac compressor?

I suppose.....although I have done it, fan for space, belts for ease of removal of alternator and AC, loosen alternator to get to wiring plugs at rear and AC because if you unplug it you'll loose the charge.

Because you want to leave the ac motor in the bay without disconnecting the pipes, so removing belts is necessary

As above and getting anything and everything that's easy to remove off gives you space to work and see. Removing the fan and Ancileries doesn't take very long, get the radiator out the way etc. Space is the enemy with these cars.