Do I confront her sooner to let her know that I'm aware that her boyfriend has been staying there and that she's in violation? 

But perhaps use less confrontation verbiage than I've exampled

That violates Fair Housing laws.It also comes across as unprofessional and kind of confrontational. 

If you are trying to avoid confrontation this is also the one with the lowest rent so focus on that and get him out. 

(I'm not a people person and like to avoid confrontation at all costs.)

They also recommended newer toilets that flushed better.I had clog issues over the years, and plumbers usually can tell me what caused it, like a tenant flushing down left over food, diaper's and I can then confront the tenant.

Obviously you can't discriminate, but maybe renting to a bunch of first time out of the house college kids isn't the smartest move if 95% of the community is older residents (seen this done more than once).It's also going to depend on your ability to confront the tenant when something goes wrong.

She gave me declaration after I confronted her about not using my property for commercial use which I have it written in our month to month lease.

I leave tell her to get out NOW before the cops come, then I go around the corner to call 911, several houses down, to avoid confrontation.

I do not mean to scare you but the least confrontation you have the better At this point just let the process play out.