So there is many aspects about you want to do.
You want it to be dynamic
You want only blueprints seems to be since we cannot conver project and deadline issues.
You want it to be stored.
So that things become on the fly basically.
I just made a prototype to be sure that it is working.
What I do,
On player begin play.
- I have a list of text defines actors and its variables like, isSelected, name,description etc.
- I access file and literally parse string manually so I have arrays of data of what needs to be spawned, write into BaseActors.
- I keep changing things, selecting actors and it always writes into actors.
- Before end play I parse back items and write into file.
As said there is many ways to do it however when it comes to Blueprint only its kind of a hard subject to nail down nicely.
You can basically use unreal data tables however they are read only, with C++ you can make it a bit Read/Write however by default no.
So the solution basically comes to 
Data driven design which I like. You can use various solutions for it.
- You can make a save game object use. You populate some actors on screen. They retrieve their data on begin play and save themselves end play. UMG only talks with actors, get all actors of a class can only run once to make arrays then its just array operation. When an actor spawns they can already save themselves into savegame object, if deleted they don’t. So basically you can always have a persisten data with it.
- You can use a SQL plugin to solve your data saves with ease what I think is an overkill.
- You can use an excel plugin which will resolve your problems as fast as possible since deadline is close.