She works from home on our business but technically has zero income, however we file our taxes jointly.

If I currently own the other property in my own name, what is the best legal and low/no tax option to become joint owners?

The bank is really only looking at you for the "joint and several" liability.

(joint and several, meaning all 3 responsible for full rent on the lease)Lease expires soon and new lease needs to be signed, but 1 guy wants out in the middle of the new term and other 2 say they will find a third and keep paying full rent until they do.

I want to wholesale and joint venture with as many people as I can to build my business.  

Open a joint account with the seller, different bank, you deposit the funds, set up an automatic draft to pay the mortgage, the wire funds are from an account with the seller's name on it, should not be an issue at all. 

Do a search for "Joint Venture" on the site.  

@Mark SenecalIt probably does not make sense to start a new Roth IRA for the purposes of combining with a Traditional IRA.Say you have $100K in Traditional Funds and you contribute $6500 (the max if you are over age 50) to a new Roth.You could setup two IRA plans and use them to jointly purchase a property, but you would be locked into the equity ratio of the initial purchase, which would be something like 93% Trad to 7% Roth (depending on purchase price, and the need to keep reserves in both accounts).  

You do not need it but it may be best to use people who are familiar with the house.Check bank account make sure all the money is there especially if you have a joint account or anyone else has access to your account.Do you have insurance in place?

Since each investor may have different borrowing ability, the loan clause "joint and severally" means that the strongest investor will always bear the biggest burden.