Hey!
So I am just wondering if it is possible to add your own custom showflags to the editor or if this is something you are considering adding ?
Having a great overall experience with the engine so far 
As far as I know, you can do it by modifying source code, adding your own flag to ShowFlagsValues.inl like: SHOWFLAG_ALWAYS_ACCESSIBLE(YourFlag, SFG_Advanced, LOCTEXT(“YourFlagSF”, “YourFlag”)). Hope it helps…