If you stay in the country to 90 days, you need to tell immigration: the first time in person, the next time can be done online. If you want to stay past the 180 days (i think just leaving and coming back in is easier) than you need to resubmit basically everything you submitted for the DTV + usually more paperwork like a lease.
They want to see your personal bank account make money... If people pay your LLC and your LLC pays yourself, show that. Basically, you need to show personal income. They don't care what the business earns.
I've only read one non-anonymous poster that said they were asked how much money they had... They assumed it was the 500k, but the IO officer never actually checked and could have quite as easily been asking if they had enough cash for their trip (sometimes if 20k). YMMV