John Snow wrote:
"Now I need to address hum."

It is likely the FM kit is 100% solid-state. Filament wiring and leakage
are out of the question.

Shielding is necessary on low-level, high-impedance audio wiring.
Continuity of shields and their supposed connections is mandatory.

Low ripple is needed in the d-c power supply. The placement of the
supply and its components must be isolated so that these do not induce
a-c into sensitive circuits.

Ground connections within the FM circuit must be sequenced and arranged
so that a low-level circuit is not sharing the ground return of a
high-level circuit. This imposes high-level noise (hum) in the low-level
circuit. This is sometimes called a ground loop.

I recall solving the phono oscillator hum problem just by putting enough
distance between the oscillator and the receiver.

Best regards, Richard Harrison, KB5WZI