Does the reverse work? Can I reconstruct my Twitter follows by scanning mastodon for Twitter handles?
So if you wanted to move to Mastodon you can't just use your export as a source.
You would need to hit their API first to translate which I suspect they will remove at some point soon.
'contact' because boost / like is included, not just replies.
Scanning tools only have to look at fediverse profiles, not all posts, but can cheaply verify if they are true.