Well there is no telling where rf interference is coming from in a 6 unit complex.

Though I may have missed a tone control-cap-ground vs tone control-cap/tube-cap-ground connection. There is a truly thick sounding texture that feels unreal (read overcharged) via the tone control, the matching of old to new cap is probably too much extraneous voltage or capacitance (right? If it is too off, it really is 'too much').

Otherwise, the input never stalls, squeals or drops out like the radio does.

I'm not quite sure what you're saying above, but if I'm not mistaken the tone control in that radio is part of an active feedback loop. So if for instance you had a cap of the wrong value in that loop you could get a pretty peaky tone response at an undesirable frequency. Their intent of course was to compensate for frequency response at various volume settings. Although it seems some manufactures at the time period went too far and started using the bass boost as a sort of selling gimmick.

I need to check the tuner schematic but my other two radios, including a giant RCA solid state console radio/tube tv do not drop stations.

I missed a cap or two.