Using glitched canavas

I'm not sure about the first part, but yeah Bungie doesn't allow glitched maps in matchmaking (they're laggy).

 

If by glitch you mean Budget Glitched, then yes. You can delete the budget glitched objects to free space. Be careful though. If you delete a wall and it was your only one, you now have no walls.

 

Not true scope, if you delete a wall, here are the steps to get it back and re-glitched.

1.Save
2.Quit.
3.Start game
4.Spawn wall.
5.Save.
6.Quit.
7.Press X on your wall to go into the options screen (or select it from the build menu)
8.Change the run time maximum to one more than the amount placed on the map (in your case 2)
9.Save
10.Quit.
11.Enjoy
12.Profit?

 

This will not work if your budget is zero or below, but you are correct.