#4
If it were in A it'd be Dorain, if it were in C it be Lydian and if it were in D it'd be Mixolydian. If theres a G anywhere in the song i'd bet its just G major.
#5
Quote by Karmekarten
If theres a G anywhere in the song i'd bet its just G major.
This.
Only play what you hear. If you don’t hear anything, don’t play anything.
-Chick Corea
#6
G doesn't even have to be in the song. You're not implying modality, and the D wants to resolve to the G. What you have listed now is a ii - IV - V in G. A pretty common progression that just wants to resolve.