Looking for tips or language to add to a lease (especially during covid) that better protects the landlord against tenants choosing not pay.

What language?

There are some other requirements around language in the company's operating agreement, but like the self-certification, that's likely something that could be done at this stage, too.  

My contractor can handle the work if he has the plans, he is just not comfortable dealing with the city on permits (I think because of a little language barrier).

If you're helping him out it's simple; get him in touch with a local Realtor who speaks his language.

I was already expecting to go in that direction because I know how sensitive this can be but I'm also trying to weigh the costs of hiring the attorney versus what can be recouped in delinquent dues (although I do know that our CCnRs have some language to allow us to recapture this in the lien as well).

Your note should have language in it regarding survivorship.

There is language in the lease that could probably be used for an eviction case but it's not black and white.  

From what i've researched the requirements range from "nothing required by the IRS" to "the PA language can make or break the 1031 validity".  

Follow your contract’s language regarding their loan contingency and cancel the contract as soon as you can……or demand a decent non refundable deposit and hang around.