Reach out to a variety of lenders, as banks, credit unions, private lenders, etc., all have varying terms.

I understand that one needs to have separate bank account and possibly credit card to separate rental income and expenses but just asking about from the tax filing purposes. 

Wanted to see what my best options are in this situation:I want to borrow 200-250K as a NRA(non resident alien) with no credit history, to invest in a syndication deal.I have a rental property that’s owned free and clear worth around 750-800K so in case of a cash out refi my LTV would remain low.It would be a short term loan: 2.5 to 3 years at most before I pay it back. 

My two favorite accounts to follow are BeardyBrandon and Investwithace. 

When you advance money to the developer, does it go into an escrow account so they can only use it for the construction or can they just take your money and flee to South America?

Most accountants will be comfortable with an exchange on a property that you've owned 1 year and change. 

Account for future rent increases by implementing value-add strategies and including provisions for annual rent escalations in lease agreements.

It's a great jobs program for attorneys, accountants, and QIs like us.  

Even though you are buying new, I would still account for vacancy, maintenance, and cap-ex when calculating cash-flow.

This is probably a tougher one considering most Hard Money / Private lenders that are go-to for BRRRRs like this focus on residential only - your best bet might be private money found here or in person networking or a local bank / credit union.