I dont like using telegram for things like this because cheaters can easily make multiple telegram accounts and abuse system.
Idea for voting is not bad but it is better to have dedicated website or use something for voting in bitcointalk forum, just dont allow newbie and inactive accounts to vote.
I have already answered these questions in the two posts above.
I will just say briefly -
ACCESS TO THE TELEGRAM GROUP WHERE THE VOTING WILL TAKE PLACE IS OPEN TO EVERYONE, ONLY AT THE INITIAL STAGE. In the future, access to the group will be limited.