It's a bit tricky, actually (since I don't know how technically-inclined you are), but I'll answer as best as I can.
1) If you apply the mod, it will overwrite some of the game's script files. Only the choice displays are changed, not their functionality, so you can choose to not go for my recommended choices. In this game, though, the effects of each choice is displayed, at least. (Who/what gets or loses how many points.)
2) As mentioned in the above point, files get overwritten, so once it has been applied, it cannot be uninstalled. You'd instead have to install/keep two separate copies of the game in two separate folders (something like "MonsterCollege-1.7.0-pc" and "MonsterCollege-1.7.0-pc-MODDED"), where one copy is unmodded and the other is modded. You can easily transfer saves between the two.
3) I believe URM and my mod might play together nicely. I haven't tried, but from what I know, URM places itself as a layer on top of everything (without modifying any existing files), and there could be some uninteded/weird effects on how choices are displayed.
4) Aside from installing something like URM, if you're able to read Ren'Py code, you could just extract the mod by itself into a separate folder (not inside the game folder), and read the code as you play along. When I've encountered a new game that only has a walkthrough mod that's for an older version of the game than the one I downloaded, I have sometimes done this myself. I open all .rpy files in a text editor that supports opening/searching multiple files at the same time, and then searched out a dialogue phrase whenever I encounter a choice, or just the phrase "menu:" (which is the most common Ren'Py function used for displaying choices).
That, or wait for someone to make a walkthrough document with all choices.