Hitler had discussed several times in 1941 attacking the US. I'm unclear on his reasoning for considering it, and deferring. Perhaps he understood Japans plan and was waiting for that to develop?
We'll never know. But in any case, the behavior of the US Administration has weight in the decision.
As for withholding supplies to Britain; Tafts inauguration would come while Cash & Carry was still the primary activity. Lend Lease was not yet spun up. So most goods enroute to Britain in the Spring of 1941 were purchased via private contracts with US companies, and mostly paid for in advance, or through secured credit. Interrupting that transfer of goods, and halting future transfer means a suppression of free trade in war material that had developed after the Nuetrality Acts were repealed in 1939.
In fact, I forgot that Cash & Carry was already in force (my bad), and I don't think Taft will try to stop that entirely. As far as I know his positions - and I'm not really well informed - my guess would be that he'd never come up with something like Lend-Lease. Not doing that means interrupting the supplies, sooner or later.
So:
- Almost certainly no Lend-Lease, at least not until the scenario changes further;
- As to Cash & Carry, a strict reading of that would mean not using US-flagged cargo ships;
- No "neutrality" patrols, no involvement of USN warships in a shooting naval war.
That's still pretty good news for most of 1941 for the Germans.