About the food dungeons, anybody can equip a food item to the weapon to make it as long as they at or over lvl 100. Also they are twice the lvl of the person who made it. So if a lvl 100 person made it they will be 200, a lvl 1000 person makes them 2000. So once u get a lvl 5000 char u can make them 9999.

As for Archers they if u lvl them at the same time with the other tech users, she has the second best TECH stat in the game for a generic char (prinnies are number one since they have access to bombs and have 6 accessory slots rofl ). This is just my opinion though so dont take it too seriously.