I will work on a case by case basis from there to defer or temporarily reduce rent.

Perhaps working out a bit of extra time to pay rent is realistic due to circumstances though asking for a reduction in rent is nonsense as lenders won't be reducing mortgage payments nor will tradesmen be lowering their prices due to the Corona Virus. 

I am thinking organizations that will help them pay rent, utilities, etc.One that I am aware of is Catholic Charities: https://ccdocle.org/program/emergency-assistance-servicesPlease add to this thread as you see fit; we can all benefit from this information being shared with our tenants to reduce the impact on our clients.If there is already a thread about this in another forum (current events, landlord forum, etc) that I didn't notice, please let me know/link it here.Thank you!

If our numbers trend at a flatter level, it will reduce panic and could stabilize this as we fight through it.

Using a HELOC to invest in other property is a good idea if you know that you can handle the payments but remember your mom would be using her house as collateral like you said, HELOC's have a variable interest rate and you would essentially be reducing the equity in the house. 

I was considering on waiving all late fees and reducing my rents across the board by 20%.

For those with experience, what is your big picture approach / policy / advice for how we should handle our tenants and these requests for reduced or no rent as they come in? 

As a proactive measure we reduced their rent by 50% for the month of April and will look at May in a few weeks.

It isn't the same because there are different problems this time, that may or may not affect RE, if we don't go into a prolonged recession we are likely to maintain the status quo, if we do the likely culprits to affect RE are oversupply due to people forced to sell because of job loss and a reduced buyer pool also due to job loss.

You can put more than 20% down to make it cash flow, but that reduces other numbers like your cash on cash return.