For the vast majority 1 LLC and 1 checking (operating account for income and expenses) and 1 savings account (for security deposits and prepaid rent) and then as @Nathan G. says over here you might find a 3 account useful:  Do you have one bank account for all of your LLC?

I think the difficult part with your advice is that New England multi family market is extremely competitive so going after something worth 1M might be risky because people are just through junk out with a price tag and the CF doesn’t mAtch up all the time.

Don't be surprised to be turned down for a place or requested to provide a larger security deposit.

So asked for bank statements to verify 3 months of rent, but they have no savings.but their credit score is fine and no late payments or evictions.wondering,  if that should be consider may be with extra deposit or not?

On the other hand, if they are returning your deposit-I'd also ask for interest and any other fees that were paid (eg inspection, appraisal, etc).

Or the deposit and pet deposit combined has to be under 1.5x the gross monthly rent?

Get a properly screened renter (thru a reputable property management company) who signs an annual rent agreement that pays you with ACH direct deposit monthly.

Showings need to continue until the lease is signed and the deposit/first months rent received.Many applicants look great until the screening process begins. 

Also could do the llc and open accounts and deposit the start up capital in it.

What do you think about deposit-free options for residents such as security deposit insurance?