No I do not see this as an issue, many have stated that back in the 80s, the credit card interest and auto interest was eliminated and both have growth and seen new heights in their respective businesses.

This will be important given potential tax changes in 2018 which will perhaps eliminate your use of mortgage interest paid on your personal home.

I'm curious if you've considered other strategies to improve your cash flow that would eliminate the need for a bridge loan potentially? 

Lots of impediments to eliminate, mitigate or incorporate, a practice based on another well-worn adage...."

The last time the house sold was back in 2010 for ~144k. 3 family house in question has its issues(older home, older heating systems probably)  but I would like to own it as it would: 1. eliminate my driveway/snowplowing issues 2. add to rental portfolio 3 increase monthly income 4.

The problem with having a co-signer is that it does not eliminate the risk of late payments or having to evict.

Focus on paying off the CC and car loan (both sources of bad debt), and eliminating bad money habits - this is absolutely fundamental to long term financial success.

The fact that you declined someone is a risk by iteself, legidimatly or not - if you never formally decline anyone, you eliminate the risk.

If the partners agree to specially allocate one item (for example, capital gains) 80/20 for economic purposes per SEE safe harbor, the corresponding tax amounts must also be allocated 80/20.However, IRS has a framework that can reallocate the partnership items based on the “ partner's interest in the partnership” if IRS determines the method of sharing the partnership items lacks the “Substantial Economic effect” (SEE) To meet the SEE, there are strict rules to maintain meaningful capital accounts including Deficit Makeup Requirement for those accounts.With the requirement, the partner must at some point contribute sufficient capital to eliminate the deficit, and the partner has the burden of the loss that partnership has and the allocation of the partnership will be respected by the IRS.This is a very high-level summary of the rules and is not comprehensive. there are many exceptions as well.Since the substantial economic effect, safe harbor allocation rules are complex and requires considerable additional recordkeeping, it's easier to follow PIP standard. 

Yes your return will be less than you're used to but it will eliminate the majority of your headaches if you can find a good property manager.If you do decide to sell, selling one at a time will probably net you the most.