Pre Painting issues help

We are new first time homeowners coming upon a mountain of problems concerning vermin, critters, electrical nightmare and last but not least paint. The ladder being the one thing we hoped we could tackle without more hemorrhaging of cash out the door. But I fear we are at a point where we may need professional help. In a last ditch thought I wondered if there was a forum to reach out to and bam what do you know.... potentially a godsend. I hope.

So here is the problems that we need direction from. The texture on the walls here is hideously done. In every term possible. Its inconsistently heavy in some areas and then light in others. Additionally that had tiny holes all over for what we originally thought was stud finding attempts by the inept. Now we think otherwise, more on that later.
So we picked our paint and began preparation. We started filling holes with spackling. Then sanded the areas where large gobs of texture was found or other relatively hideous areas. This is where our first perplexing problems began. Instead of sanding down like normal into the different coats of paint and then drywall. It bubbled and then began to peal. Using a scraper every paint layer including the original texture of the house (which is atleast 6 coats and 2 other textures layers deep) came easily up. Additionally the underside of the peel has a red or orange tint to it. Which suggest some indication of rust which has me pointing to moisture.

Thoughts up to this point? Where do we go from here? Handscrap it all down to bare and repaint??? Will it do this again? Whats the cause of the failure ion adhesion?

It may be important to point out that the house is brick 4 sides and framed from steel not wood. Which may or may not account for the rust color I'm not sure. Upon opening the walls to the frame I am not seeing indication of rust on the beams but I'm sure a tiny amount in a sealed area could still be the culprit. Again though this is entirely based on a uneducated guess.

Please help!