I just had a few thoughts for guardian deities and namedays, since they do nothing ingame atm:

For Guardians, I was thinking that each deity should have unique bonuses that are always active on the character, based on that deity's element and in-game description

Using Oschon the Wanderer as an example:

Wind affinity +5
Magic Accuracy +2%
Evasion +2%

My other idea for namedays would be for the duration of the day, your character would gain a small bonus in all combat/magic/crafting/gathering stats (say 3~5%). Since the Nameday only comes once in a long while, I doubt it would be game breaking. If you have any other constructive ideas or thoughts, feel free to add them.