Are you able to get some pics of where you say the starter is laying up against the block? Reason I'm asking, I was looking at the pics you posted and it doesn't seem to be hit where the perimeter frame would impact the engine. Even though there is spring memory, usually the area of initial impact would show more distortion. I've seen some caved in vehicles in my day which is why I'm suggesting a closer look and to not take the starter laying against the block too lightly. Usually, a wheel hit does it.
I don't know if you mentioned whether or not the engine mounts are still intact. Anyway, please check around for other secondary damage. That's damage caused by the hit but indirectly from whips, motions and other components. I don't recall which configuration starter is on there, but they are usually pretty close and some have a torque bracket on it.
There isn't much meat where the starter bolt holes are from what I can remember. So, if the starter is pushed against the block from a collision, something had to give. Cast iron and aluminum won't deform or bend much before a noticeable crack appears.
The side of the block where the starter is are cooling fluid channels. You may not see a leak until the block expands and contracts somewhat. Something I'd look deeply into before I start tapping my wallet.
Seems like a nice project though. Please allow me some time to catch up to all of it so I can let you know if I have any usable input. Also, let me know if I off base here, just trying to help.JP