I know that's added cost, but is it worthwhile, or just focus on digital marketing?

Would you doorknock and tell them this, send a handwritten letter, walk the dogs by and just start general convo, like it was not planned :), or something else?

Whatever it is draft up a letter and send it certified mail of what the issue is and the steps they can take to resolve it.

Could be that you don't need to move them to a business account and just show you've had them for 60 days and it could be that you don't need to season them at all, just a bank letter saying you have the funds available is sufficient. 

For actually sending out letters, input everything into excel, and then use microsoft office's "mail merge" feature to merge the applicable house / contact information into your letters. 

Make sure you are targeting motivated seller and are hand writing these letters.

A firm demand letter may help get your commission check released that you were owed in early February.

I want to provide a proof of funds letter so I was going to go with hard money, but the hard money lenders are sending me a preapproval letter for cash instead, defeating the point of a cash offer.

Typically, for most of our clients we work with in similar situations, your lender will ask for a letter of explanation as to why you are moving. 

Maybe you're great with digital design, or marketing, or personal outreach - it could be anything.