You could... but, in most cases, I doubt that hunting down the lower-level ingredients would be any faster than letting AE find them itself. Unless you're making octuple compressed cobblestone or something... which requires testing.
I don't know, but I doubt it. It might slow them down more if you use a higher casting mode, though.
I don't think you can... at least, not how you're thinking.
If you use a higher casting mode, you'll get a larger area. Crescent-moon mode gives a 3x3 area, half-moon mode gives 5x5, full-moon mode gives 7x7, if I remember correctly.
The inscription table won't actually let you create a spell that starts with "Dig"- you have to start it with "AOE" or "Projectile" or "Touch" or whatever. If you do "AOE | AOE | Dig", the spell should (if I understand AM2 spell grammar correctly) create an AOE action that does nothing save create another AOE action that destroys nearby blocks. I don't think that the first AOE action will create multiple copies of the second centered on different blocks, but it might. Also requires testing.
If you do "AOE | Projectile | AOE | Dig", you should get a spell that makes all players (or mobs?) near you involuntarily shoot a projectile that digs out an area around whatever it hits. This could be considered "stacking" AOEs, but it's not quite what you were thinking.
Probably not, but you should back up your world, just in case.
Usually.
Probably not. They usually announce if the next update is likely to break things- but, like I said, make backups, just in case.
I doubt you'll need to regenerate config files- the mods will regenerate individual lines that they find missing. However, if a mod added a new block since the previous update, the default ID might already have been given to another mod, which will create a conflict and crash your server. Should this happen, you'll want to replace your config files with those provided by FTB (or fix the conflicts yourself, if you'd rather), not have the mods regenerate them and create even more conflicts.
