I definitely think the F#m chord (or F#m7 chord) could be considered tonic, and I said that in my original post. It is certainly the most stable chord in the progression. But just because it has the notes of the tonic triad does not make it tonic.
Traditionally speaking, bar 1 of a 4-bar hypermeter is the most strong, bar 3 the next strong (but weak with respect to bar 1), and 2 and 4 the weakest. I’m OK with tonic chords happening in any hypermetric location, so I’m not sure what you’re arguing.
I’m not sure what your example of I IV/ii ii IV is trying to prove. (Also, why wouldn’t we just call that progression I V ii IV?) Sure it contains forward motion, but having the strongest bar NOT be tonic, the chord progression contains more forward motion. Most prechorus sections are structured according to this strategy, and they push forward to the chorus very strongly as a result. Again, this is a commonly-known feature of chord organization and rock music.
You seem to be conflating “key” and “scale” (or “key” and “mode”). Those are two very different concepts. A minor key is NOT in essence another scale. It is a collection of relationships between harmonic entities (among many other things). This is why we expect a major V chord in minor keys yet a bIII and bVII chord as well. The concept of key is quite complicated, scale much less so.
The major-anchored convention is called the “popular” style of notation and was developed and first employed by jazz, pop, and rock musicians (who now use it as their main means of notating harmony), long before it was adopted in academia. So there is no grounds to say I prefer it just because I’m in academia.
You are indeed correct that the label of “major” or “minor” for the key becomes somewhat redundant for the pop style of Roman numerals. That is kind of the whole point. Mixture is too great and prevalent to use a Roman numeral system that is tied strongly to traditional distinctions between major and minor (or on modal collections). My whole point is that songs which HookTheory users identify as minor keys have been employing a different system of Roman numerals, which is not the way working musicians or academics chart songs.
Again, I’m not trying to argue for the primacy of major keys or major scales, based on the harmonic series or anything of that nature. The pop style of Roman numerals simply uses the major scale to label harmonies as a convenient reference point. It is exactly because we want to better keep track of all those different harmonies - all those colors you talk about in your last paragraph - that we use this method.