3 requests | MuseScore

That looks like 5 requests to me, but 3 is a reasonable engineering estimate I guess.

For 1. Have you checked out the different types of input – see musescore.org/en/handbook/4/alternative-note-input-methods

For 2. Select the item you want to nudge and use the arrow keys on your PC keyboard – see musescore.org/en/handbook/4/adjusting-elements-directly which also describes other ways of achieving the same thing

For 3, and 4 look at this part of the handbook. musescore.org/en/handbook/4/formatting it explains how to set up your score to avoid the issues you mention.

It is not clear what you are hoping for with No 5.

Note that it usually best to keep to a single topic in a thread so that it is clear what topic any replies are related to.