It is better to reject for any violent crimes and waive issues from non-violet crimes and/or crimes from long ago. 

The exception is if it was a violent death (eg murder) and that may vary by location.

Lots of so called interest but no follow up.Facebook Marketplace and groups webpages get a lot of interest, but most of the groups are garage sell type groups and that is the type of prospective tenants I get, will you drop the rent, will you work with me on the deposit, will you accept no credit check because mine is bad, "you should not count my domestic violence 7 year prison term as a violent felony because I really did not hurt her", will you take less for cash payment and no written contract, can you furnish it so I can list it on AirBNB? 

Had they renewed the contract and there was mold left, of course a mold waiver would go into the contract as well.Second landlord lesson:  I was house hacking and one tenant's background check came back with a violent event but he was a smooth talker and explained it away and I let him move in. 

Unless it was a violent death, and this wasn't, you don't need to disclose anything. 

He has also made violent threats against the former board member.

At least not those where their felony is related to a violent crime. 

Does anyone know if I can remove him faster for his violent behavior?

We ultimately allow our owners decide, but recommend that non-violent felonies are ok.

If as a result of your negligence, a tenant injured themselves so severely and at such a high cost for medical expenses, that the tenant's health insurance company's claim against your property policy, and deemed it monetarily worth their while to bring suit against your homeowners policy holder, I would say you have a whole slew of more pressing problems like overcoming the urge to complete your "violent art gallery show" where in you hang running chainsaws from the ceiling of other people's homes in an aesthetically pleasing pattern.