Do I have to amend my already filed 2019 return in order to do so?

I am not a big fan of filing amended returns so I personally wouldn't go that route.

Have them contact their insurance company and file a claim, but you pay their deductible.

Is there any benefit to having a copy or is it fine to leave it filed in the county alone? 

Too bad for those partnerships that already filed for PPP without including their active partners' compensation.

It requires you to provide financial statements and tax returns.See here: https://www.sba.gov/sites/default/files/resource_files/how_to_disaster_app_March_2020.pdf

Did you file a claim with your carrier first?

@Alexis Terry. white pages.com. tax records. public settlement filings. linked in. online pay services. google name search (name+state) about 60% of the time you get employers name, then you call office main number and ask for the person you want)

What do you suggest about filing insurance claims?

Proc. 2000-37, 2000-2 C.B. 308.Notice 2020-23 states that the coronavirus-related relief provided in earlier notices generally applies to all taxpayers with a tax return filing deadline or payment due date between April 1 and July 15.