1) No. Because OnEnable can fire multiple times, and you should be creating frames once, then reusing them. Same with font strings, or any other create once, reuse element.
OnEnable can fire when you reload the UI, or when the user toggles your addon on/off if you have such a feature.
2) No. Mainly because that doesn't exist. There is only one OnInitialize function, one OnEnable, and one OnDisable.
You should look at the full Ace3 documentation; it is very thorough, except for handling modules. Also, ignore the parts about embeds.xml and list any files and libraries directly in the .toc file.
https://www.wowace.com/projects/ace3...etting-started