That reminds me that I opened my BoA checking with a bonus (the paltry $100 bonus) ...and used Serve to trigger it, so don't be dissuaded by a direct deposit requirement.
With the Preferred Reward levels, those are determined by how much you have combined with BoA across all accounts. When you're first starting out, it will be the average over a 3 month period. Once your 3 month average hits a qualifying tier (25% for Gold/50% for Platinum/75% for Platinum Honors) then you start earning that bonus.
Last year we transferred out our brokerage account in March, but retained the bonus earning until last month. BoA sent me plenty of warning letters that we would lose our Preferred Rewards status, and I opened up a Merrill Edge account for a new account bonus in January and we're back in their good graces, without starting over on the 3 month average (which was surprising to me). That's 10 months of bonus earning without tying up funds in BoA. While that wasn't my intention, I'm glad to know that.
Joint brokerage accounts will count toward the qualifying tier amount for BOTH account holders, which makes it a bit easier to qualify P1 and P2 for bonus earning potential on each of their individual credit cards (hint hint).