Hey, welcome to ASC.
1. Well you can do that, however since locaps hold 68 BBs (if i'm not mistaken) that'll take you some time. Plus it will get a bit tougher as you add more in. The loading rod comes with a new AEG so just use that, or a hand speed loader is a good idea and don't cost much
2. Locaps are good if you are into the milsim, and don't mind carrying around a bunch on a field. Hicaps are good if you are just plain trigger happy and need all that ammo in one mag, however they do rattle a bit. Midcaps are in the middle, they have a good size ammo capacity without the rattling of hicaps. However many midcaps have been known to misfeed, jam or need some oil or working in out of the box.
3. You don't need the winding tool to wind hicap mags. Winding one with your hand is fine.
4. There are many players in AB. Check the teams section for people in that area
5. That all depends on what you like. If you like the look of the AK, get that. If you like the look of the MP5, get that. It all comes down to personal preference and what looks good to you.
Also, you might want to check out the games section. Even if you don't have all your gear and guns yet, it might be worth it to head out to a game. There you can meet some players, get any questions you have answered in person and get to see some of the gear and guns up close to see what you like.