Hard to say because it's been a long time since the original Mighty Mite. Some individuals would auto others would semi auto, a few would finish in late August/early September.
Size would vary from 1.5 feet to 3 feet. The later ones could get to 6 feet. Never prune it's a bud on a stick type usually.
these MM are fully auto, but without lowryder genes. That means that they will flower under 24h of light. They will get around 1m height.
Great breeding tool since unlike LR, you don't end up with an autoflower at F4+