I would like to install one optional mod that I didn't manually select while going through the Overhaul installation and setup. Is it possible to run the Overhaul setup launcher in a way that lets me install the one mod that I want to add, while not affecting the rest of my installation? -- I found the answer to this, and installed the mod I wanted

Also, I can't click and hold on the + / - symbols while bartering, and have the numbers quickly scroll. I need to click once per 1 increment of value, something which makes trading very troublesome. I assume this is a conflict caused by a mod, but does someone know how I can fix it?

The only thing I have installed over a clean install of the base game is Morrowind Overhaul, using custom install settings.

I also had an issue where music stopped playing after the end of a track, and no further music started.

Open the MSGO Options. You can make any changes you like, without going through the entire set-up process again.

Isn't that how it works in vanilla?
I thought it only went fast when using the FPS Optimizer or MGE (both of which have options to make it go fast, IIRC)

Or, you're getting uneven FPS, which can cause some menu buttons to act weird.
Open your Morrowind ini file and change this line: Max FPS=240 to Max FPS=60
This often improves the frame rate flow, and improves the functioning of some menu buttons.

Nothing else comes to mind right now.

I thought it always let me click and hold for rapidly scrolling the values up/down. If there's an option in MGE, I missed it, though I went through everything pretty thoroughly. I'll check out FPS Optimizer.

Edit: Oh, I didn't go through MGE yet, only MGSO. I'll find it in MGE then, thanks! PS, do you know what option in MGE toggles this functionality?

You need to use 'Macro Editor' in MGE.

http://sourceforge.net/apps/mediawiki/morrgraphext/index.php?title=Macro_Editor should make it clear. It details macro editor for MGE but its same for MGEXE too, whichever you chose to install while installing MGSO.

PS : Also dont forget to install these http://download.fliggerty.com/download--726 http://download.fliggerty.com/download--852 for MGSO if you haven't. First one corrects many problems concerning tables, doors etc. The second one fixes daedric armor error.