For this: "There's that thing about a free loan on the 6.2% employer share of FICA tax"

That's not quite how it reads.

The various provisions are:

Employer Share of FICA deferred 50% and 50% payment schedule.

Employee Share of FICA and Fed income tax withholding optionally can be retained by an employer who qualifies for the retention credit, Sick/Leave credit, etc, allowing the Employer to keep the funds as an Advance on that credit, or to also use Form 7200 to request the refund if their employee share is not high enough to cover that credit they are entitled to.

The 940 payment is not affected.

The forms are not affected.