Welcome, Buc.
You landed in the right place for peppers. Consider starting a glog to document and get assistance in trouble-shooting for your pepper grow.
I haven't the foggiest notion of when to plant squash and melons in LA. But, I would highly recommend direct seeding vs sprouting for transplants. They have a very narrow time window of OK vs root-damaged. By the time a transplant recovers from transplant shock, a direct seeded plant will usually over take it since they grow pretty fast.