So you did have LR installed on your older MBP and you had at one time synced LR mobile with a collection in the LR catalog file on that older Mac? Is that correct?
Do you still have the older Mac and do you still have the original LR catalog from that older Mac?
Never ever delete any catalog files. Even if you never plan on using them.
I don't work with LR Mobile at all (tried it when it was first available but stopped using it after a very short time) so I have no idea if those images and edits can be retrieved.
We will attempt to recover your edits. Will respond directly to you via email once they are available.
let me know if you need anything from me