@ciane Tried the 'constrainfloorelevation false'. No luck while trying that way, so I rolled it back to a backup from this afternoon just to be safe.
@SimTresa I tried that... it seemed to work - sort-of. Messed up the whole pool in the yard (attached), and it's attached/butted up to the one in the basement, so that makes me a bit nervous. To move everything down I had to go in and move the basement down also first as it is apparently effecting the ground (seems to be the area not leveling, so that may be the issue). I'm trying again to see if moving the basement down before leveling will work. I'm nervous about the pool. It wouldn't be a big deal but I have way more hours on this than I'd like to admit and it is a huge mansion. Really wish I hadn't toyed with these terrain tools first. :/ I'll update here after trying this...