When a property averages less than a 7 day rental period over the course of the tax year and qualifies as a non-rental activity, and non passive tax treatment, how is the rule about personal use affected?

The correct treatment would be that each of you would have been reporting a % of the activity of the property as tenants in common in the absence of any other ownership structure.  

But the two may not mix.An intermediate product like a TIC is a good thought but since what makes the tic qualify for 1031 treatment is that you take a deeded tenant in common interest in the real estate, it too must fall under the regs.

Don't give special treatment because a relationship didn't work out, most don't.

For a property to be eligible for 1031 treatment it must have been purchased with the intent of holding for productive use - not for resale.  

In case it is a single member the taxes are done on your personal return.If you want a more professional treatment I suggest you contact Borders and Borders real Estate Attorneys.

one tenant said she has bed bugs, we sent pest control for 3 times, and didn't find any bed bug, he called city, and city said even he caught bed bugs some place else and placed into a jar, and showed to the inspector in the apt, we have to do a bed bug treatment?

And don't expect to get that treatment as a tenant.

Tenant's General Responsibilities: Tenant, at Tenant's expense, must:pay any periodic, preventive, or additional extermination costs desired by Tenant, including treatment for bedbugs, unless otherwise required by law;"I would double check, but as long as you have been reasonably proactive to try and help with pest control, the tenant doesn't have the right to cancel the lease for pest issues. 

you may need to inject treatment into the ground, too, if there are subterranean termites.