Great idea. Though with all ideas, I have some comments to make:

In some guard chapters, there is a beginner rank (ex: squire in the Vigilant chapter). This rank is automatically given to everyone who is accepted via app. Squires patrol with full members, and after some time IG and IC to learn the ropes, they are promoted to a full member. This method allows players to prove they can handle the position before giving them all the power at once, which leads to smooth RP.

As for formations, it's impossible to do them IG. This is because different players have different connection speeds, which means differences in output. When a commander says "march," some players will notice the chat before others. As such, the lines will get crooked. Parade drills would go the same way.

To solve this issue, emotes are usually used to say that the lines are uniform, even when they aren't. Players just wouldn't be able to pull off perfect lines due to minecraft mechanics.

There can be drills at times or spars held to practice RP skills, but executing them IG is next to impossible.