As long as you are running a compatible lever, yes.

Absolutely - it's up to you what Shimano level you are most comfortable. 105 offers the best value for money.

yes, the fixing bolt is standard. But the length of bold is longer for front brake, so you must buy one front and one rear brake

Yes, I have done the same change on my husband's Allez. A great improvement on the brakes supplies with the bike. Go for it.

Yes, it's a universal fit

Yeah they are both recessed bolt road bike brakes so they should fit. Pretty standard really.
These also work with v-brake style mtb pads like the ones Kool stop make. You just need to switch the washers around the opposite way so they fit it. This can depend on the clearance you have with your front forks though. Rear usually work find but sometimes the front forks are too tight to fit the extra large pads in.
If you can fit them though its worth it as stopping in the wet is so much better.

I think you would be better replacing the brake pads with a good quality after market set to get the most bang for your buck.

Try Swissstop or Kool Stop