I guess I can see converting "destructively" to avoid the realtime resampling.
I'm not sure why you think it's a destructive process?
When I do that in my DAW, it will just generate a new file at the new rate...the old file is still intact.
AFA the OPs tracks and mix...mmm...they need work, but then, it's really up to him how much work he wants to do. I don't mean just figuring out how to make the vocals sit better....I already took care of that last night with some basic cut/adjust edits, and got the vocal to a much more acceptable level-balanced state from start to finish...otherwise, if it was me, I would redo a lot of the tracks, especially the guitars because they are simply out of tune.
I know that I get a bit too sensitive about tuning, and I can see that a lot of folks simply don't mind or don't hear it...I'm just saying that to make the song sound much, much better...I would redo them I think only one of them sounds in-tune, because it's mostly power chord stuff, so you just hear the low strings, which don't show tuning issues as much as the higher strings.
That said, I think with the vocals level-balanced, and I also did some tweaking on the drum "stem" track to give them more clarity and snap...along with some tweaks to the bass guitar (also level-balancing and some EQ...the OP can take those tracks and add/replace to what he already has, and I think his original issue of not being able to tame the LUFS to acceptable numbers...will be solved.
I mean...the tracks could use a lot of work...OR...take the basic fixes and just go with the rest as is. It's not something that will be fixed with plugins. It's more about re-tracking everything there is a desire to improve on it substantially.
Anyway...I'll try and finish up today/tomorrow and send them back to him to check out...otherwise, it would take a lot of work & time to redo all this stuff, and not something I'm going to get into. I mean, it's really for the OP to do, since it will also help him progress.
Of course, but Vegas Pro is also a video editor so it's designed to accommodate assembling projects from files that aren't necessarily recorded in the project. There's nothing stopping the user from resampling files before importing them if that's preferred. Given the power of modern computers it's hardly noticeable when a mismatched sample rate file is used.
Yeah, I also have Vegas...but in the case of audio files that are "attached" to video clips, that's a bit of a different situation. it's not as straightforward to convert, but then, most video is shot with the audio sample rate at 48 kHz as the default/standard...so the clips should have the same sample rate for the audio...though it may not always be the case if someone had a good reason to use something other than 48 kHz.
That said...IMO, if it's a small project with only a handful of files/tracks...there's no reason not to take the step to get everything set to one reference...
...and if the project is rather large, than IMO, you really should make the effort to get everything set to one reference.
It may not be a show-stopper if you don't...but like I said earlier, IMO it's just sloppy not to.
Not trying to embarrass the OP, since this is just a impromptu helping hand situation... but after downloading all his files (and there aren't a lot, I think only like 20 or so) it still took me awhile just to sort things out a bit, and I'm still not done (busy all day with other stuff).
The naming convention was unclear in some case...OK, I know that he knows what it all means...
... but when I see 10 tracks with "EG1, EG2, etc"...I can only guess it means "electric guitar", but it doesn't really tell me what the tracks are about, only the type of instrument used. Likewise seeing the multiple sample rates, and sorting out what all the tracks are supposed to be doing, and just getting things cleaned up and organized so it's clear what your looking at and what your hearing...is important, IMO.
So I could not see myself ever working with multiple sample rates just because DAW technology lets me do that. It's just easier when it's neat and organized.