I think this would be more of a long-term hold for cashflow purposes, however it seems minimal to start, and I feel there is likely little to no appreciation with this property. 

I've been a mortgage broker twice as long as I've been a surfer but I think the professional experience might truly be about to pay off!

In terms of getting into apartment complexes and large transactions - it's much easier than you think.Real estate is filled with opportunities to deploy capital, but in the same time is filled with fast-talking snake oil men that will happily take your money towards a "fund" so you own a portion of a large portfolio... only to find out the fund's performance is below par, your money is locked out, and the only person making money is the fund manager from the management fee they've locked you into. 

Your current mortgage payment will not affect DTI as long as you have a future tenant lined up prior to closing on your new primary. 

You can explain that any changes to the lease must be carefully considered, as you want to maintain the original terms that protect your interests.If you decide to allow the change, you could draft an addendum stating that each tenant is responsible for their own rent.

Also file a complaint with the CFPB Submit a complaint | Consumer Financial Protection Bureau (consumerfinance.gov)Regarding do you have any legal action - you can prove you do not owe it but you will not get any compensation - courts have ruled long ago the only recourse you have is actual money you lost - there is no "pain and suffering" if a statement is incorrect and you have to fight with them on it.

Is that due to the long term projection looking better?

Regarding payment terms, the seller wants 10% at the reservation of asset (this month), 10% in a couple of month, and the balance at the signing of the deed of sale in December.

How long would it take to pay off? 

They focus on finding long-term tenants, and it's a win-win as less turnover is less expense for us and less work for them.