There is a pitch envelope on the lead sound. It scoops into the note. The same sound is also used to play the chords. I also think there is no regeneration on the delay.
Here's my take: In the beginning of the song I feel like they automate the delay (the engineer recorded changes in real time aka old school automation). You can sort of hear at the start of a bar how it's more instant. Which is giving the echo a strange slap back feel that's way more in your face. There's a sort of phasing quality to it that could be from the timing feeling a bit off or due the hardware having more fluctuations in its processing circuitry which plugins tend to have a hard time emulating which you mentioned. (If anyone is interested search for SSL Fusion plugin doctor comparison as an example). The soothe2 plugin was a great addition that you made to balance this and it did add some of that character. But Spectral processing is maybe a bit too clean in this case. // Maybe Gulfoss is better. Or a small addition of a hardware unit (Clark Teknik has a copy of the chorus you used and I've heard it's great on mixes for width.) They both cost about the same amount of around 150 $, which is crazy. If you still want add a more analog hardware feel to the sound with software then it should be also be doable with more modulation/automation to achieve analog type non-linearity. Like adding LFO's and Envelope generators to parameters etc. Anyways you did really well it's crazy how much distinct character you produced with the processing chain. Great video and cheers!
Spent a Staturday night following this, substituting the odd plug-in I didn't have (Fab Filter Timeless for Pulsar). Fairly pointless as I'm not in a covers band, but an interesting exercise.
I realize I’m 2 months late hearing your version. The ValhallaRoom sound your actual notes are too high. It should be bummm-bumm-bummm not whhhh-whh-whhhh…Best way that know I how to describe it.