Oh, they look absolutely fabulous! GREAT job! If you're not growing in enriched soil, you could start them on a small dose (1/4 - 1/2 strength) of nutes right about now... if your soil IS enriched, I'd put that off until they start "telling" you they need something. Since they're autos, you can expect them to go into pre-flower in week 4-5 and can start bloom nutes then to get them ready for flower.
Reading through all your questions and all the problems you've encountered, I've got to say you're a very thoughtful grower and I think you'll get through this grow in GREAT shape... good luck and enjoy the journey!