Removing stickers

It depends.  Some bikes, like my old Bianchi have a clear coat over the stickers so I could not remove them without sanding off the clear coat first.  If the stickers were "stuck" on after all the paint work was finished, you could probably peel them off slowly with possibly adding some heat from a hair dryer or heat gun.  Any residue could be removed with rubbing alcohol.  I use that instead of mineral spirits since rubbing alcohol is not as strong.

I "de-badge" all of my cars.  I take off the model name emblems on the rear of the car.  I can do this by slowly peeling them off and I have never damaged the paint in any way.  I like the minimalist look!

Nah, blowtorch works best - burn the suckers off!

There is a product called Goof-off that works great with decals and stickers.  Shouldn't harm the paint. 

You can also just peel them off by heating them up - and then you are left with the stickiness.  There is an excellent, non-damaging chemical for both aluminum and carbon fiber frames that you most likely already have in the house................

Creamy Peanut Butter.

I kow it sounds crazy - but I tried it when I head about 6 or 7 years ago and it works.  Do a test on something you have laying around the house - you will be shocked.