Some engine mounts are available with removable studs or come disassembled. When this is the case you only have to jack the engine 1/4"-1/2", use a saw to cut the stud between the bracket and the mount, slide out old and slide in new and thread the new stud in from on top through the bracket.
Depending on your packing gland arrangement and shaft length from gear flange to gland you may not even have to disconnect the shaft.
If you don't have a style mount with removable stud, as well as the shaft you may need to disconnect the exhaust at some connection. Typically electric and water to pump can tolerate enough movement that you only have to watch them as you jack the engine.
Often its easier to do front or back 2 at a time and not all 4 at once. Also if you can jack with load on the stringer and not the hull, or use a chain lift from a reinforced overhead connection, it is much better than on the hull.
Going back in with same / same mounts is always easiest, and change in brand/size often opens a can of worms