Tell them you are willing to write a new lease curing those violations.

That didn't cure Problem #2: two low estimated bills followed by a whopping big bill for actual use in the third month. 

Just give them notice to cure as it is a violation of the lease. 

Serve them a "Cure Notice" which is telling them to follow their lease agreements and you will point out the part where it talks about keeping the property clean.

Give him notice to cure. 

For example, my lease states that in the event of a smoking or pet violation, I may then charge a $750 fine in addition to charging the security deposit as needed to cure any effect of the lease violation - such as damage and/or smell.

That said, as @Nathan G. pointed out, it takes about 5 minutes to cure the other deficiencies. 

Every lease/state law is different but you will probably need to submit some form of documentation and then a cure time.If the threats are serious enough, have Tenant 2 order a restraining order.To answer your question: do you just start the eviction process? 

If it is in your lease, give her notice to cure and tell her if the items are not removed by a set time, they will be disposed of. 

Turn around time is 4 months. 1 month for that is the foundation cure time.