Fits but depending on what you mean by upgrade, a b550 might make more sense as it can house the next generation. Also, since you have a graphics card, a graphics chip in the cpu is pointless (3200g).
There are 2 x USB 2 plugs at the rear. You can connect whatever you want. I have a mouse and a data cable on it. It works.
Internally there are more USB 2 connections, but only for direct connection, e.g. housing.
The problem may lie with windows. Windows likes to hide things in the onedrive (user>appdata>roaming) which can cause trouble. I had the problem with Gigabyte Fusion and Asus Aura and then realised that it can't be the software. It can also be due to the ENE software - you like to uninstall it because you don't know what it's for and suddenly mystic light etc no longer works properly. (or you find "Patriot RGB" in your programmes, think you don't have a Patriot ssd and simply uninstall it without knowing that some manufacturers use the same code).
Suggestion would be to do a clean install (worst case from windows and then mystic light), and leave automatic synchronisation of windows (activity history & onedrive) deactivated. Select "Save files only locally on this PC" in the corresponding question during the windows installation.
If this does not solve the problem, it may also be due to the fact that different RGB standards (digital/addressable 3-pin & "standard" 4-pin) are connected at the same time. Unfortunately, this does not work in general. It is always either or, even if both standards are actually supported.
Hope this helps!
So the Realtek® ALC892 codec is pretty good and it's a gaming motherboard so you shouldn't have any audio problems.
But please have a look at the manufacturer's website for answers to all your questions and more.
https://www.msi.com/Motherboar...