well I reckon,people should play just how they like.
If I was playing irish tunes on a 5 string ,I would be tempted to flat pick them,because thats what I have been doing on a tenor banjo.
the g chords emi and c chords would sound good with the high g string.
I am finding[I am only just learning 5 string]that drop thumbing,comes naturally[having fingerpicked a guitar],.what is taking a lotof time is one finger frailing,because it is completely alien to how I play guitar,which is thumb and three fingers.but it keeps me out of mischief.