About synchronizing code: it is not so easy like in Q3 and such engines. In UE is souce code connected with assets more closely. For example when you want to change default HP of player, then you have to do it in UE editor, not in C++ code. I think that for working simultaneously on more versions is possible, but merging it together is almost impossible.

About AI: UE have own AI system and should be quite easy for default game. But I think, no, I know that for this custom game it will be much more work/problems.

The raw surface of the gamelogic should be sufficient to help smash out basic physics and related bugs without a need for leaking potential security and the alike. Synchronising source changes isn't needed with the availability of patch submissions however it does mean that the user's end must always be updated and patches needed to be tested for potential clashes if the user's end isn't updated or if an update rolled between the user finishing their work and a new update that is related to the section of the gamelogic (e.g. an update may rework the routing order of the marauder zap, user fixes the way the marauder zap hit detection system)

Speaking of which, we need at least a publically announced regular dev game going to help boost the population as it is.

Regarding bot AI, I can provide some advanced concepts (that no other game from what I know has yet to combine) to the aiming system so they won't be so aimbotty but it will require the use of the latency compensation system similar to quake's unlagged or a similar memory system to feed off. I have not seen how the UE3/UE4 system works so it may or may not be easily applicable.

When you will get your rewards?

Badge on forum: now (just tell me that you really want it)

Coupon for item shop: when will be item shop implemented

Place in credits: DONE

VIP status forever: when admin system will be implemented

Place in credits in book: when book will be finished

Special skins: when skin support will be added (after item shop and admin system)

H^ola

Okay, so the current way of preventing taunt spam is to have the system mute the player's text communications.
I think that's a bit unnecessary, as it then means they can't communicate or vote just because they spammed the taunt a few times.
Would it be better to have a "cooldown" period for the taunts after excessive use? Since even after the mute, the player can still taunt spam.