We currently have joint ownership of an LLC that owns the property.According to several lenders we've spoken to, we can either take out a joint loan to execute a delayed financing option immediately, or wait 6 months and refinance with an individual loan on the name of one of the partners.

The pertinent language is on page 19 near the bottom on this document: " ... households are groups who have chosen to jointly occupy housing, and that “rent-by-the-room” uses are not permitted in single unit, two unit, and row house zone districts."

That would allow you to have a great, low interest fixed-rate debt on them and conserve cash for other investments.Ultimately you and FIL's agreement can be between the two of you, or it can be official, usually in the form a management agreement, operating agreement (of an LLC), or some sort of more complicated agreement like a Joint Venture.  

Wondering if there is joint place/website to see the rental tenants situation :)

I believe that buying and holding would be great under a joint entity for a long-haul, or scaling endeavor.

With that said, we are looking to open a joint bank account for this venture, and obviously are looking to do this remotely.

For a married couple filing jointly, only one spouse has to meet the ownership requirement.

The first is that if you reside in a community property state in the USA, which treats properties owned jointly by spouses as being a single owner (simplified explanation!)

However, if the tenants left the place in shambles and you lost 3 months of rent this year because you had to put the joint back together, you can sue for those 3 months.

NO PM CO would ask an owner  to open a " joint " bank account.