This is very unlikely to be officially sanctioned. I would rather look at reasons why the things above have to be edited this way / what is stopping you from making your own models and address what we can.

There are some of the reasons why it should be edited:

• Samples, models can be used as samples of thing it represents
• Buildings, some of the buildings/buildings parts aren't enterable
• Memory points of models, memory points are required in order to correctly layout some of the things like particles
• Hidden selections/general selections are required for the same reason as for memory points
• Animations in the model config, doors, rotating parts, etc
• Custom actions, containers, in most parts require view geometry to be edited, have specific selection
• Resizes of some models
• Fixes of some models just because not everything can be/is fixed

Things i personally would like to have/to do

• Wrecked model of some buildings, such as fuel station, since DayZ Expansion mod includes explosive fuel stations and with the wrecked model of one it would look more natural
• Doors in some buildings like hangar in krasnostav airfield
• Hidden selections in models such as camo net, cases, and etc in order to make hologram material

My use case for the ability to edit every house is properly add a proxy to all the doors so I can attach an object such as a code lock.