Generally good. If you wanna hit the ground running, they're good choices.

If you decide you don't like them, they can be uninstalled too.

Personally I prefer qbittorrent and VLC, and have installed them, but I've used all 4 and the mint defaults seem perfectly functional.

The good thing about Linux is: preinstalled literally just means preinstalled. Not preferred, not prerequisite, and perfectly uninstallable.

But that's all I have to say. You can test each and see if you like them, or look up what people think of each individualy. If you don't like one, just uninstall it, and install your preferred alternative.

You are on Mint, so it is more of a Long Term Support LTS distro. The thing to understand is why LTS actually exists in the first place. The underlying reason for LTS kernels is so that anyone can create a server that is connected to the internet and uses simple high level scripts to connect software and do useful stuff. Many types of software are constantly in a state of flux that break backwards compatibility. Actively developed software in the open source world often stays up to date with the latest packages. Other distros like Fedora or Arch stay up to date in the latest software. If you write a script on a server that runs one of these distros it will likely require regular maintenance. If you write the same script on a LTS kernel distro, your script is likely to work the same for years without any need for intervention. In this LTS arrangement, kernel maintainers are committed to back porting any security patches required for the packages they include in the distro. Some of these packages may already have their own independent commitment to never breaking backwards compatibility. These will still get updated regularly in a LTS distro.

So the choices the Mint packagers are making are centered around LTS like stability. Many of the packages may be outdated especially in the glue and obscure edge case software in the native software repository. You may need to manually add sources to get newer versions in the package manager.

This fundamental understanding of what a LTS kernel means is key to understanding Mint overall, and by extension the reason most distros exist; they all have a niche purpose.

I don’t use Mint so I can’t talk too much about the software choices. Transmission is a simpler more user friendly torrent client. It used to be the go-to client on Mac, maybe it still is. I find it a bit too simple so I use qBitTorrent as well.

You’ve moved to a completely new ecosystem. There’s lots of software out there and most of it’s free so give it all a go. I know in Windows when you install something and then remove it they always seem to leave traces around. Linux is much better at cleaning up so there’s no real reason not to install something you want to try.

i typically uninstall firefox for firefox nightly, thunderbird for thunderbird beta, and then use qbittorrent instead of transmission personally but it's all just preference. there's nothing wrong with celluloid either; it's a nice little player. i just like vlc more because i'm used to it.