Revisiting this, you could - theoretically - cut down on the number of characters you have to copy/paste, but it would mean adding one more state to the dialogue.
Looking at the one line with the multiple possibilities...
++ ~I like bugs.~ + response2
Then further down your D...
IF ~~ response2
SAY ~Oh?~
IF ~RandomNum(3,1)~ THEN + response2a
IF ~RandomNum(3,2)~ THEN + response2b
IF ~RandomNum(3,3)~ THEN + response2c
END
And then you could put the part of the NPC reply where it's different in three separate states. Ultimately, it doesn't matter. Once the mod is traified, it's all going to be @345 or whatever anyway.