However, I think since we're planning organized transport, that this
really won't be necessary, since as I'm expecting it they'll just
"enter" the country.
No one can "just enter" any country. If law requires papers/visas/letters for residents of some countries than that will 100% be case. I think we rely too much on some phone call, "intervention" of someone etc.. which could go in wrong direction for some people..
We could have list of ppl that require visa and we could (month at least before Debconf) arrange signature on that list of minister(s), president(s) that they are allowed to enter country.