ADBrown

Depending on what product you are pairing your FBV with, you can sometimes use tap tempo to color the rate or speed of other effects phaser, flanger, tremolo, etc.

On your Helix change the output block to the desired USB channels, probably 1&2. This should keep the dry guitar sound from passing through Helix and out to your speakers. 

From the menu where you select your amp/cab/effects blocks you can choose the Impulse Response block. The first controllable parameter of the IR block selects which IR is being used. 

I don't have any experience with the 2 wireless systems your bandmates are using, but I think between the 3 devices you should all be able to run wireless. Just take the time in finding the best channels for each of you to use. 

Yes, you can switch channels on an amp via the M13 and midi. I have never attempted this but after poking around on this forum I see many users have successfully done this. I found where someone has made this work with a JVM that might be of interest to you.

http://jvmforum.com/phpBB3/viewtopic.php?t=8556

There is no delay when switching presets via foot controller. It is pretty instantaneous.
 
Unfortunately there isn't a way to assign the tuner for instant on/off. The "hold for tuner/ tap tempo" is the only way to access the tuner on the amp or foot controller. It really only takes a second, but I understand your situation may not allow for even that! 

Hi, I was able to get the g10t to transmit to both a Spider V 60 and the G10 receiver>amp simultaneously. Sync the G10t to the receiver, then on your Spider V amp hold down the home button for a few seconds, this will bring you to a menu where you can change the wireless setting from manual to auto. From there you can choose which channel you want to use on the Spider V amp. You will have to manually sweep through the channels and find which channel the G10t is on. Once you find the same channel you will have sound coming out of the Spider V as well as whatever your G10 receiver is plugged into.