If you can find the proper blades at the BB stores you should have no problem. I've never seen blades that are the same size and have the same bolt sizes at a BB store. Length, width and thickness are going to be your problem.
Depends upon who made the blades.
I use Oregon & Stens which most of the time are almost identical.
OTOH I have seen a lot of cheap blades that are exactly that, cheap, a little thinner, a little narrower, a little shorter cutting length and God only knows what grade of steel they were made out of.
If there is a brand name stamped into the blade then most likely they will be OK at worst.
If no brand name then best avoided.
