As far as balancing the prop goes, don't worry about it.
I have never balanced one yet and believe me I've been through alot of em. Just twist her on and go for it.
I think that the prop manufacturers have got them about as close as 99% will ever need.

As for question 2. Which bolts?
Firewall or engine flange???
If it's firewall just take off the muffler (to access that side) take one out at a time/ clean it off apply a little locktite and screw it back in.
Another trick that I've done is to lightly damage the threads. Take the bolt out and squeeze the threads with a pair of pliers to LIGHTLY damage the threads. (stay about a 1/16" to 1/8" back from point so it starts good) screw it back in and your done. (you'll feel the added torque putting it back in)(that's what ya want)

If it's the engine to mount bolts go with longer bolts and NYLOCK nuts.

Question 3.. Alpha engine
Aren't those preset from factory/ already broken in.
(I need more info)