I always like to have a vent below from the front to put in fresh air. It is just me. Depending where you live, you can open/close any vent from below to control air/temperature. I think pigeons are healthier with lots of air. This fancier, for example, puts a lot of vents (click on the portable loft): http://www.skylakesions.com/index.html
You have a very nice loft, but could you please use hardware cloth to cover all openings, as predators can get easily thru the chicken wire.
The fencing works for the aviary, but make sure any openings for the birds to get out in the aviary are closed at night, because you would be suprpsied at what can get thru the fencing larger then 1/4 inch openings.
I have chicken wire and hardware cloth doubled over with fencing (because my neighbor gave it to me) on my aviary, you can't just use chicken wire by itself , re-inforce it with hardware cloth is best.