They did say by doing the substitution he wouldn't have any day off so I'm assuming from the start it was a kinda of performance with side a and side b,what is a bit confusing but what confuses me more is like...were they the only characters that weren't being played everyday or was like really half of the cast worked one day and the other half in the next??
Because the audience paid to see Len’s rendition of the character. In reality, a situation like this wouldn’t happen. More often than not a lot of the electrical productions have something called a “swing” which is a member of the cast who’s available to sub in for another cast member at any time. Specifically for leads, they should have an understudy. In this case in particular, Fuginaga what have just gone on and that his portrayal of the character, but I’m pretty sure this was done specifically to showcase his abilities and not necessarily done because it was the most suitable solution.

Wait but then who is performing his character? I think he is he doing both? But don't they have scenes together