1. Definitely dual boot, especially if you’re new to linux, and double-especially if this is what you use for work. You are likely to run into situations where shit just doesn’t work and you need a fallback environment to operate in while you figure out what that’s about and how to fix it. Likewise, you will run into software that runs badly on linux or just doesn’t run at all even under wine/VM, and it will be nice to have that fallback for when you don’t have time to fuck around and figure out what the problem is and need to just get shit done. If things go well you will find very quickly that you don’t need it and can probably go ahead and delete it after a little bit, but at first you want that lifeboat. Mine stuck around for 2 weeks, but I only even used it the first couple days and the rest was ‘maybe I’ll run into some weird situation…’ and just not needing it. As for merging the partitions and such, I believe that’s possible, but you definitely want to make sure you have backups before you try it just in case. There are many good cloud backup services that have linux native clients (I use filen.io myself.)

2. I’ve never even touched music software so I have no idea what’s out there. I do however know about a great website called alternativeto.net that lets you find alternatives to existing software, and you can select your platform to limit it only to linux software. For example, here’s the entry for linux-native replacements for Cubase (it was the obscure one from my perspective, wanted to see if they actually had anything, turns out they do.)

3. Yes, NTFS generally works mostly fine on linux, though there are a couple of weird cases where it causes problems (one I ran into was adding games I had installed on an NTFS drive for windows to Steam on linux, it was very wonky.) After nuking my windows boot drive I went through and copied all the stuff off my NTFS drives and reformatted them to btrfs before putting the data back on them to ensure that everything would work smoothly, but if you’re just using it for regular file access you should be fine. The one caveat I would add is I would probably not recommend editing large projects in files on NTFS drives in linux if you can avoid it, but poke around google and see if you can find people reporting issues with your specific software/use-case to see if there are any problems with it.

4. Drivers for weird hardware are potentially an issue. Looks like there is a FOSS driver for the Scarlett, didn’t see anything at first glance for the Behringer, but also again I have no idea what I’m looking at here so this is something you’re going to have to do some research on. I have had some weirdness with audio in general on linux, things cutting out unexpectedly, stuff like that, but that’s strictly games/discord/that sort of thing, so it might be worth looking for stuff other people have posted about doing heavy audio work on linux to get an idea for what to expect. I’m sure it can be made to work, but it might require more fiddling than you expect.

Either way, welcome to the party. :)