Welcome To...
Can a number be duplicated with Bis more than once, on both sides, or can a Bis house be copied again?
Yes to all. A house can be copied repeatedly on either side (for example 5bis-5-5bis), a Bis house can itself be copied (later copies are called ter, quater and so on), and you can write bis copies next to each other. The only condition is that no fence separates them, so they all stay in one estate.