Thank you both so much for your responses! I figured this might just be a dead post, but I really appreciate your help!
I definitely know now what you mean about noisy power now lol. I rewired everything to run off my 4.8v green pack. And while it all "worked" I was getting a ton of feedback if I switched the fans on.
But your absolutely right with the two batteries, I think that's probably really the best way to go. I got my fan on the power bank, and I bought a separate battery for the velleman, after testing the system. It only 3.7v 500 mah so I guess we'll see how long it lasts, during a troop. Lol P.S. 3.7v should be plenty right? The kit came with 3 AA so I figured it'd be fine.
Somehow I got it all to fit in my helmet, I have the velleman piped out in to some headphones, and also piggybacked my radio comes into the same speakers. And let me tell you.. coolest part is hearing your mates over a com channel, instantly makes you think you're really in star wars Then I got my fan and voice amp mic, plus a ppt button for the radio in there.
As you can see, this one is going in my Mando helmet
Again I really appreciate yours guys help! Very awesome of you!