But since I owned multiple units that were collecting income I could go through the eviction process without any repercussions of my personal bank account.  

Not my cup of tea, but Boston has a lot of great things going for it that in the long run I think you could make it work.If by multi-family though you mean a 5+ building that you're presumably going to look for in the Midwest or South...it's in its own bubble as a disturbingly large number of people who made bank in the last 10 years of the up market are shifting their focus to a larger scale asset and are purchasing these distressed properties which is driving cap rates down because people need a place just to park their cash. 

I could get a travelers cheque or a bank draft.

No bank, no bank hassles.

Is there any bank or other corporation that we need to go through to obtain a loan?

Soon is defined as 5 years or less.So assuming that’s the case your best bet will be high yield savings account (ally bank is around 1.75 percent I think) or a money market account

I used deal # 2 as collateral with my bank to secure the loan and 3k out of pocket to purchase this unit.

If so then I would look into 2-4 unit multifamily and get a 203k loan, this allows for minimum down payment and you can buy really messed up homes and use the banks money to fix it. 

The platform is associated with major U.S. banks so most tenants have access to it through their checking accts.

Our bank said it can sometimes take up to 10 days to show up.