If you can share enough data that I can write an importer, I can see what it would take.
I would be seeking the bounty. This is my day job. I would also offer to run imports for people with budgets, as each one is surprisingly different. Once I’ve run an import to get the code to work with one site, I’d share the code. I’ve got at least one person interested in an import, which could make it worth my while.
I’ve written several importers.
I will share the code.
There is no issue with long term maintenance! This game will be over in a few weeks.
If you can get me the dump you have I can see about helping match those Google ids. I think that what you suggest might be possible, but I’d need to see the data to tell for sure.