With my region common events script, you would have several different common events - one for corn, one for rocks, etc. You then decide what region id you want to use for each one, and then draw with that region code wherever you want that common event to be called. It is set up per map, so you could have region 1 on map 1 call the common event for corn, and region 1 on map 2 could call a common event for flowers or something like that.
You would not use a region script with an NPC, because NPCs are events anyway, and can also move around. And in most cases you don't want all NPCs to say the same thing. So you would just do each NPC individually, or if you DO want them to say the same thing, you'd use the Call Common Event command.
Scripts are safe to use. The only times there are "bugs" is if you don't use them correctly, or if they're fairly new scripts and the author is still fixing things that they may not have tested.