Are these companies actively accepting resumes already or should I hold off until August to submit?
If you meet all their requirements I'd apply sooner than later. You can always follow with another email late in August if you don't here back from them. If you go with Skylens you can find the directions on their website and there's a thread already in this forum where the owner will update if he no longer needs pilots. http://skylensaerial.com/pilot-employment.html