(1) If we should be a registered user in meta in order to vote.
Yes, please create account on Meta-Wikipedia. This will be useful for future votes as well.
(2) If we should vote in individual language-wiki.
No, project-wide votes should be held on Meta.
(3) How to count votes of those who have multiple usernames across multiple languages.
For now, we need to count on honesty: one person, one vote.
(4) If we need any weighing of votes by language - balancing voices from less-populated wikis with populated wikis.
I don't think so. Equality, liberty etc.
(5) If we care preventing a username.
??
(6) If we need some time to make translations of the voting page in multiple languages.
I hope English will be good enough for now. Syncing votes across several pages would be a pain.
The more I think about this kind of procedural difficulties, the more I feel uncomfortable relying on voting as a measure of conflict resolution.
We should always seek a consensus first. But if that is not possible, the only alternative to some kind of voting system is to rely on a single arbitrator -- in our case, Jimbo.
Especially when the stake is high and there is some serious disagreements, I suppose designing a good voting system could be very difficult. We might need some bureaucracy for it.
I don't think so. We primarily need software support for whatever voting system we choose to implement.
Another possibility that I can think of is multi-staged voting.
Yes, if complexity gets too high, we need to split up the issues into stages.
Regards,
Erik