Visit visa for mother in law

[treefriend]

Thanks Ben. Very helpful indeed.

I am planning to apply for Irish stamp 4 next week. However my mother would send her application in the mid of next month. Is that OK? Or we should wait until mid of next month. My concerns/points are

When my employer would ask for stamp4, i need to show it therefore want to apply asap
If we wait to send our RC application until next month, then my mother would have same address as us and therefore we don't have to show much documents to show her dependency on us. (living in same household vs dependency phenomena)

thanks