Ran some tests. Was as I thought.
Standard: 40 (that's +32 all CS, +4 base +2 host, +2 something else)
Killing a CS no longer lowers the total vote required, unless it's Austria/Venice. Because it removes the CS entirely (you can never liberate it), the vote goes down by 1.
In total, for the first vote, you can have 50 max delegates (Forbidden Palace, World Ideology, World Religion, 6 spies), unless you're England, who gets 51. This means it is impossible to win on first vote peacefully if more than 5 city states have been captured.
It is impossible to win on first vote period if more than 10 city states (11 for England) have been gobbled up by Austria/Venice. If Austria/Venice gobble up all the city states, you will need Forbidden Palace, World Ideology, World Religion, 6 spies, and can only win on the 4th round of voting.
I haven't tested how removing a civ affects the requirements since fall patch.