Have you submitted these bugs to the engine team?
The ability to have a full scene in a BP is essential for AR use where you typically want to spawn objects at run-time. The FBX import into level option even has the option to import as BP.
Please could you implement the option to import as BP (like FBX) and fix the convert to BP option?
The team seem extremely resistant to this idea. I appreciate it complicates the reimport functionality but I and others really think it is essential.
Thanks for considering this.