Yes, it's that lot which the grocery, theater and bookstore reside on; while I was vague, I did mention that Add Any Size Lot mod.
I get the two errors "Cannot Place on Lots" and "Cannot Place on Roads" at certain distances from Central Park: As close as possible (touching the adjacent road) is the former while going back (where the front line is adjacent to the back of the bistro) is the latter. When getting the building(s) into the library, I had to enter a different Sunset Valley save file and copy that to it since it wasn't there normally. The lot itself is 64x32 (same as the local school), which is why 63x32 won't work (1 length too short).
I actually don't get the unroutable terrain error, amazingly.
At present, I grabbed the theater from Twinbrook, the grocery from Outdoor Living Stuff and the bookstore from Hidden Springs as temporary replacements.