as with everything, it varies breed to breed. but they will have bumps for a while. They probably won't start growing significantly until he is around 8+ months I would say
during the day is the perfect temperature to put them outside!
at night it might be a bit too chilly so i'd either move the lamp or move the chicks back inside
depends on the natural size of the breed, the first one has much more complete/even feathering than the other 2 ( i know no.3 is a transylvanian naked neck but still)