Clean up and simplify breps for honeybee energy calc

I often need to do energy calc on larger files with many crooked breps. Some of them not closed, others just deformed. Redrawing them all is a tedious job, and one that I would like to avoid, but I simply havn’t been able to produce a script that works and has the ‘right’ level of detailing.

The outcome needs to be simple closed breps, but still have the information of negative spaces, different floors/heights, slanted roof, etc… The overall shape should be there, but it doesn’t need to be precise to the cm, although if the breps represent rooms next to each other, they do need to fit exactly
I’ve tried lofting a projection, i’ve tried convexhull, i’ve tried cocoon, amungst other things

Does anyone have a solution, or perhaps just a suggestion?
Hope you can help!