What types of IRS/CPA approved payments are working well for rents to LLC entities to keep personal and business funds from co-mingling? 

@Robert EllisAre you leveraging construction-to-permanent loans or private funding?

We closed the bank financing at 80% LTV at 4.5% on a 20 year amortization and 5 year balloon.

I personally leverage, but have a large rainy day fund. 

Tell the tenant you will only accept payment in full with certified funds.3.

@Adam Newman you will want to confirm this with the bank but you can’t take a loan out to borrow for part of the down payment so you’ll need to provide all the funds yourself or have a gift from someone for that which you don’t have.If you have a gift from someone to bridge the 20%, that would be ideal.  

I have used them to fund a flip and I would absolutely not use them again.

I'd be willing to bet buying an index fund would have a better return without any of the headaches. 

Funny you mention the whole GP / LP thing - I spoke to someone recently who claimed to have raised $10M+ for a fund and owned over 100 units.

Greatly increased lending capital by transitioning from a ‘blind pool” fund to a series LLC / syndication model where investors know the property lending deal before committing to any loan and can “pick and choose” whichever loans they do or do not want to participate in.