BIG BARN for digital film and music production

This is as far along on my project as I have gotten so far: It's a large piece of Northern California countryside with only two neighbors who's homes are hundreds of yards away. There is an occasional jet flying over head or kid on a 4-wheeler, perhaps some distant cows, a rooster, goat....all very sparse and seemingly, not much to contend with. We are building two places from the ground up. A live space (granny unit) and a work space (Big Barn). I have the current floor-plan for the Barn here. The aim is in the direction of full-scale independent digital film making; including music creation, Special effects, and eventually 5.1 surround sound. I've been pressed with many other issues of this project, and haven't been able to fully grasp the immense sea of knowledge there is on the topic of studio design and construction. I'm sure I will get plenty of critiques here, but that's what I'm here for. Currently, I work out of a suburban home (2nd floor bedroom 9'x9'x14'), 2 mackie Hr824's and I make music for television, produce corporate videos, motion graphics work and, currently a 90 min animated/live-action HD feature. My house looks pretty crazy on the inside....green screen in the kitchen, two drum kits in the living room, a photography shoot going on in back, a room full of props and nick-nacks, another with hard drives, my studio-room and bedroom. The main problem I have currently is not neighbors (well, not complaining anyway) it gets hot when I record, but I can hear the noise from the air-conditioner vent on the mic (window too, of course).....so we have to do little spurts of 10-20 minutes or so, and then it's just too hot and we need air....I'm currently in Davis, CA and it is much hotter here than in Sonoma County, where I'll be moving. But I think this is more just body energy heat because it happens at night too. It's an overflow. so, we aim to do it right, if we are going to do it from the ground up. I've always been a D-I-Y kind of guy so, no matter what I end up with, I will do with what I have....I'm just trying to be as future-proof as possible here,... so to speak. I'm in a position to plan and create this "dream" in my opinion, and I'm planning for things that are far beyond my current necessities...thus, I need your help; and I'm trying to give as much info as possible. So here is what I've got: The full Barn is about 100' x 60'. There is the "unconditioned" space, and the "conditioned" space. The later is where the studio is to be. I'll do my multi-genre, electronic music making in there. I want to record in the mix room as well as 2 vocal booths and band room....as well as the unconditioned space. The mix room is planned to be 13' 20' 24' (HWL)...I want to have enough space to have people functioning in there....sofa(s) etc. I have a computer room to the side to house the noisy computers and hard drives and maybe a utility-office. Right now, I only plan on doing double-doors on the vestibule (entry), band room and computer room. Is this insane? or thrifty? or ...i don't know. I just figured that...well, What do we really need? I don't think huge low's coming from the mix room are gong to be a problem for the vocal booths...you tell me. My main question is actually about air right now. I want to cool (at minimum) the mixroom, all the recording rooms and the computer room. I've heard about the ductless mini-split system which seems good, but it doesn't get "fresh" air into the studio. Then, I think about (at most) cooling the entire "conditioned space" with a super quiet low speed central-air system....and I don't know much about if these exit or how expensive etc. Will having a duct in the mix room effect the acoustics?...how can this be done. I'm willing to explore a more manual method (say, opening the doors every so often to get fresh air) but, I'd really like people's advice or perspectives on these issue...especially in relation to the designs I have currently. The materials...I really haven't gotten that far. I have a contractor / friend who is on the job....along with an architect who drew up the plans so far........ Okay, I'm running out of info....... what else do you need to know? Thanks so much for any advice or comments.