If I have 2 scripts; Aircraft-Action1 and Aircraft-Action2, can I run these inside of a third script, Aircraft-Action3?

yes, you insert them as an event in the script editor and you can also use flow control to do things like pause X amount of milliseconds between the two or three scripts.  I have a script for the PMDG that runs an after-engine start set of tasks that has about 10 different scripts inside of it separated by different time intervals.  Like having a copilot do things for you.  I even activate it with a voice command "After Engine Start Check"

It looks like this

2701·(>K:ROTOR_BRAKE)(SPLIT:500)3001·(>K:ROTOR_BRAKE)(SPLIT:500)0·(>K:#69750)(SPLIT:500)2·(>K:#69751)(SPLIT:500)2·(>K:#69753)(SPLIT:500)1·(>K:#69832)(SPLIT:500)1·(>K:#69833)(SPLIT:500)0·(>K:#69843)(SPLIT:500)1·(>K:#69834)(SPLIT:500)1·(>K:PMDG·737-HYD·PUMP·ELEC·1·ON)(SPLIT:500)1·(>K:PMDG·737-HYD·PUMP·ELEC·2·ON)(SPLIT:500)1·(>K:PMDG·737-HYD·PUMP·ENG·1·ON)(SPLIT:500)1·(>K:PMDG·737-HYD·PUMP·ENG·2·ON)(SPLIT:500)1·(>K:PMDG·737-PROBE·HEAT·L·ON)(SPLIT:500)1·(>K:PMDG·737-PROBE·HEAT·R·ON)(SPLIT:500)1·(>K:PMDG·737-TCAS·MODE·TA/RA)

Excellent...thanks!! There goes my afternoon