@paddenstoel00
Edit in game is borked depending on your versions. What I do is remove the DCache and/or Mods folder while working in EIG. It's mainly the store content (located in the DCache folder) that keeps it from saving, etc. Of course, some content won't show up because of this. DO NOT delete these files but place on the desktop or in a safe place you remember so you can add them back into your game once finished with editing. You can always redecorate your lots as you want after you have them placed and your world is finished.
As far as rabbit holes are concerned - I do not use them and prefer to use the rabbit hole rugs that can be placed in any building or on any lot, for that matter. I find that I save more space with the rugs plus the buildings I choose to use as workplaces for my sims just look nicer then the EA ones.
https://www.nraas.net/community/Building
Example - my police station -
https://64.media.tumblr.com/33fd997ba711631cff98a85a0989ad7d/2e05814dbfe8c6ad-48/s1280x1920/de823410c8e1aff3eae927ce2618ea824420d531.jpg