Yeah, "Chet" isn't the most memorable jazz album out there but I maintain that it's one of the prettiest and most relaxing. The sameness of the material does tend to wear on you if you're not in the right mood but if you *are* it's like a warm bath. I also maintain that although Chet isn't one of my favorites he has one of the most beautiful tones in jazz, probably more so than any other trumpeter (yes, even Miles in his early days) and that album is perhaps the best presentation of said tone.
The Basie & Young/Goodman & Christian set sounds typical of the rag tag jazz compilations they used to slap together back in the day. Little logic behind it but if the material's good, who cares. Yes, the vibraphonist with Goodman would be Hampton. If you mainly got it for Christian and are disappointed with how small his role is, I recommend adding this to your list: https://www.amazon.com/Charlie-Christian-Radioland-1939-1941/dp/B004QEZRIG. My favorite release of his, good sound and you get to hear him cut loose way more than on the studio sides.
Didn't know there was live stuff on "The Complete Birth of the Cool". Guess there weren't enough studio outtakes to make up a box set? That's ya boy Gunther Schuller on French horn and yeah, the balance between him, Mulligan and Konitz has always been one of my favorite things about that set.
You're making me want to dust off "Sketches of Spain". Been awhile since I've heard it. It definitely took me a long time to get into (I had listened to barely any jazz and basically zero classical music when I first heard it) but the atmosphere usually reels me in even when the music itself isn't particularly engaging. I may even go as far to say it's one of the best *sounding* albums I've ever heard, even if you do know what you mean about the dynamics (this seems to be a common problem with classical music, actually).
"Concierto" is another album I need to revisit. I tend to have amnesia about the 1st side but I do recall it being a very consistent album (and the best thing I've heard under Jim Hall's name not counting co-billings with Bill Evans). I don't remember the album being "fusion" at all but maybe you're using the term loosely?
Wes Montgomery - Smokin' at the Half Note
Though I prefer this one, "Full House"is another killer live Wes album with the Wynton Kelly Trio (only this one adds Johnny Griffin on tenor) recorded 3 years earlier than "Smokin". Have been warming up to live albums more in general these days, especially live jazz. Like many jazz fans, I realized awhile back that many of my favorite musicians are at their best in live settings so I've been trying to seek out good live jazz albums more and more lately.