Some people make good landlords, some don't, identity that.

Contact a local landlord tenant lawyer.

How can I be a landlord if I don't have any rentals??

Hello,Before moving into this house, our landlord made us sign a lease for a year.

Seeking advice from some more experienced landlords.

If it is a master planned community with a large common areas (perhaps a pool) and extensive landscaping could also be in that category.   

You also should do your own due diligence on them (background screening, calling past landlords, etc.).

They want $375k, which is laughable, as a recent comp with the sq. footage fixed up and with a pool is like 425k..I offered $200k, quick close as is, but with inspection contingency... agent responds that they owe more than that, no point in countering. 

I disagree with previous answers.If the tenant owed money to the previous Landlord, that's for them to work out.The issue at hand is something different.

He told me that we can't do that and that it is a partnership.In looking at the IRS definitions it states:PartnershipA partnership is the relationship between two or more persons who join to carry on a trade or business, with each person contributing money, property, labor, or skill and each expecting to share in the profits and losses of the business whether or not a formal partnership agreement is made.The term "partnership" includes a limited partnership, syndicate, group, pool, joint venture, or other unincorporated organization, through or by which any business, financial operation, or venture is carried on, that is not, within the meaning of the regulations under section 7701, a corporation, trust, estate, or sole proprietorship.A joint undertaking merely to share expenses is not a partnership.