Quickbooks allows for you to add multiple debit & credit cards/bank accounts associated with a company.

The 51% ownership allows for decision making in such circumstances.

Most of the time people will open doors to closets and cupboards, turn water on and off; but they shouldn't be going through dressers and definitely should not allow their kids to jump on beds. 

From a tax planning perspective, you are only allowed to start writing off the home once it is placed into service (once the lease starts).You are also only allowed to write off the depreciation, and any other costs or losses against the earnings from the property.That is, unless they get the real estate professional status, which requires 750 hours a year working in real estate.

The “limitation” (or maximum, which I believe you’re referring to) applies to the individual / employee, not to the business.

Her staff wasn’t allowed to handle money, so we didn’t receive rents for months.

However, we have a long-term plan to accumulate more than 10 properties and want to be strategic in the way we structure which one of us is on each of our loans now so that we can max out at 20 Fannie/Freddie loans in our individual names. 

You can find and connect with these individuals at local meet-ups, BiggerPockets, Facebook groups, and from other investors. 

Would you be willing to share a bit about how you found hosts to allow you to co-host for them?

In SFH neighborhoods with HOAs they are generally lower cost and keep the property values up by not allowing "yard art".