As long as that other part isn’t fixed but can vary, you’re making it hard for yourself. If you insist on that naming, you should change the name field in folder2 to either be full links, like in name: "[[001 - Test1]]", or not as good name: 001 - Test1. The first would be better as I think that in recent version it would be renamed, if the note is renamed.
The point is that any searches like that which are not linked somehow, are very hard to do within a query. It’s kind of like a sub-query, which isn’t supported. If you can build the link to the new file, you’re good as my previous examples show, but if you’re “not sure” on the new file name (aka it has varying parts) then you’ve got a problem.
Regarding your second question, see my response on another thread below: