OMG i was closer than ever, and after a few hours of debugging the source, I finally found the name.
The type I need is named “SoftObjectProperty”, but WTF it’s not in the easily accessible list, and it’s confusing.
Nevertheless, I am glad that everything worked out and my original idea is being realized 
.
Thanks to everyone who thought with me (I hope such people were here 
).
P.S. Oh, and I still haven’t been able to beat the search, so if you know anything about it, you’re welcome.