Well im going to try to ask most questions on this post.
We dont have a release date (short answer). The development is going as we understand how bully and the different systems on it works. We also take some time to rewrite some of the code to make it more stable. So we cannot give any date, but i can tell we dont want this lasting forever, its consuming the most of our free time and we want be as quick as possible. We will post here the release date when we think we can give any, but were aiming to open some kind of testing rounds before release. Will announce more in the future.
Triying to reply to those funny game modes suggested, most of all will be possible to develop with server scripting API, were looking on the suggestions to make sure we exposed enough api to develop these gamemodes will be possible, we expect massive gamemodes as P3ti could incrase the pools up to 100 peds and 200 vehicles the servers will work in MTA like scripting, using lua 5.1.4 (this lua engine has nothing to do with lua scripting present on game, for those who asked). We're working now on a wiki documenting all functions/callbacks server will have.
To reply the most modding questions, we have no plans to redistribute modded game stuff by server like MTA does, we aim to keep it simple at the beggining. Modifications on game scripts will be disabled, also all modifications that give the player advantage on other players will be blocked too. I think texture/skin modding would be acceptable, but we didnt made any decision on it yet.