This looks like extreme nutrient problems, ph problem, and/or environmental problem. It really could be many things. From the looks of it, even if someone gives really great advice, I'm sorry to say I think it'll be too late. I can't imagine it being possible to fix them. In the future you'll need to try finding a solution at the first signs of yellowing or browning unless it's only the very bottom leaves, or a few leaves change a month into Flowering.
I hope I'm wrong and someone smarter can help, but even if you do get help, your buds will never reach their potential. I really wish you luck and hope you keep trying until you grow beauties you're proud of.