Whew, you covered a lot! Nice job!
1. CtB mapping uses only the x-axis. The placement of objects varies only with the x-position assigned to it. Two objects with the same x-position will appear at the same place during play regardless of their y-positions. The y-axis is used only to space objects out in the editor space, making it easier to interpret. Placing all objects at the same y-position causes many objects to overlap, which can be very confusing to read when modding!
Remember to note that sliders are affected by the angle in which the ends are placed from their head.
If necessary, slow the beatmap down to inspect things more closely.
Exactly how do you slow the beatmap down? You might want to explain that.
Odd spacing - Ensure that the spacing between objects complements the intensity of the sound(s), and look out for any borderline dashes or hyperdashes that require near-perfect timing to catch.
More spacing = more intensity. Please explain that?
Suitability - Do the hitsounds used match the song? It makes little sense to use drum hitsounds when choosing to map a piano or vocal rhythm, for example.
Please define "suitable" more. I'm a little confused by the drum vs. vocal example.
Will look at it again more later, check for updates.
Note: I'd like to add that people really shouldn't be posting off-topic memes here because we should promote this guide. I want this thread to be about improving something that will promote the modding community. Please post stuff that actually is positive words, encouragement, or constructive feedback. Thanks.