In your case, if you are using just your own cash, you can take advantage of the "delayed financing exception" to pull cash out and put a mortgage on the property right away. 

In some states, builders and property managers can take advantage of rebates on space and water heating equipment, substantially driving down the upfront costs of upgrading.

If I were you I would tell tenant that you're willing to work with them if they have payment issues, but if they just want to take advantage of the situation, they will be getting a bill for late fees, a notice of non-renewal, and a 5 day notice to pay or quit as soon as the eviction moratorium is over.

Your PM is under an assumption this will keep people from taking advantage.

Will amortize these over 30 years for better cash flow & take advantage of the low rates.- 2 of them bought in 2020, 1 in cash due to how competitive the market was had to close with cash & am taking a commercial loan on it due to not wanting to wait 6 months on seasoning period to free up cash, 5 year ARM on 20 year amortization.

This  provides less risk but also allows me to take advantage of the 30% market drop we have just witnessed.

We are currently refinancing our portfolio in order to take advantage of lower interest rates. 

Is it best to keep the unit vacant to avoid any issues with tenants being able to make the rent payment and take advantage of the federal multi family loan forbearance?

This is a great house hack that should be taken advantage of if you can handle managing 3 tenants plus your roommate!

You are taking money that was earning money in a tax advantaged account and moving it somewhere that it will be taxed, which I'm generally not a fan of.