ADD kids in gap year - without a plan

I would love some advice about my sons. They need guidance, but as is often they case they don’t want to listen to their parents. I don’t want to leave them completely to their own devices but do not want to nag them either since it doesn't have any effect. They are identical twins, graduated from HS in June, and turned 18 last week. They were diagnosed with inattentive ADD at the very end of their junior year in HS. One son wanted to take meds and the first day on Concerta he was amazed at how interesting his calculus textbook was all of a sudden. Over the long term, I couldn’t see that the Concerta made a difference in grades. They have both been indifferent students since the start of middle school (I thought they were just lazy). Anyway, at their public high school there are basically two (unspoken) tracks: AP/Honors and Everything Else. For whatever reason, they insisted on taking the AP/Honors stuff and ended up with a lot of C grades. They are smart, funny, good kids; never do anything they aren’t supposed to do, they just frequently don’t do what they’re supposed to do. The low grades usually had more to do with not completing work rather than the quality of what they did. Thank goodness, they decided they weren’t ready for college and are taking a gap year. I told them that was great but they needed a plan. It’s nearly September and there is still no concrete plan. They both want to apply to art school to study film making, and the idea is that they will be working on portfolios. They actually have done a lot of photography over the summer with a new camera they pooled their funds to buy, and have been working on a couple of short films. Soon all their friends will be off to college (their closest friends are attending Yale, Middlebury and Oberlin) and their network and collaborators will be gone. Our local community college has quite a good art department but they have developed a degree of snobbery about CC, alas. There is a great sounding video foundations course they could take but they just won’t do it. I think they really need some structure for their portfolio-building - and support from people who know what they're doing. But they want to do it all on their own, or maybe they really ARE lazy. I just don’t know what kind of help, support, etc I should be offering. I am insisting that they apply for jobs – they need to learn responsibility and they need at least to support their increasingly sophisticated tastes in clothing – even that isn’t going so well. I said I would withhold allowance until they applied for ONE JOB. That was 6 weeks ago! One kid has applied for one job (and got an interview!), the other has not. I really feel like a dud as a parent. Any ideas?