Recovered from boot loop but constant crashes with older ROM

I am helping a friend to get his One Plus One 64GB to work again after an OTA update broke it.

Initial Problem
Two days ago she started an OTA update which made the phone reboot constantly before even android started. Basically it showed the logo for about 6s then vibrated and restarted again. I later found /o/Android/data/com.cyngn.fota/cache/cm-12.0-YNG1TAS17L-bacon-signed.zip so I assume that this was what was installed.

The phone is completely untouched otherwise. She has no computer knowledge whatsoever and says she didn't give it to anyone.

My attempt
I was able to install cm-11.0-XNPH33R-bacon-signed.zip and cm-11.0-XNPH22R-bacon-signed.zip via sideloading. The phone started ok but was crashing all the time. I am not able to get into settings to activate developer settings (adb) because the crash notifications hinder navigation and after about 10s the whole gui crashes and I see the black screen with the hexagon loading logo. The latter firmware is worse meaning it crashes at a higher frequency.

The Problem
She didn't expect any problems and does not have a backup of her data. Thus I can't do a factory reset or use fastboot.

Question

• Did I use the wrong ROM? There seem to be many variants. I haven't found any information which explains the differences.


• Could I maybe flash a minimal ROM that would not crash to backup the data and than do a factory reset?


• Is there any way to activate adb access without having to navigate to settings?

Download link for an older DorimanX kernel?

I am looking for a kernel older than DorimanX 8.43/9.43, because these not support to set "touchmove sensitivity" (vitalij value) to 0.
In later DorimanX kernels, the touchmove value is 8, and there is no option in STweaks to change it.
I know that 8.33/9.33 supports it yet.
I have googled for hours, but could not find a working download link.
I found download link just for 8.41 in a chinese webpage, but it does not support touchmove sensitivity too.

So if you have a kernel between Dorimanx 8.33-8.40 or 9.33-9.40, please upload it for me.
Thanks in advance.

Install older apk?

I just came from a Nexus 5 where I was using Chrome version 36. I refused to update last it because I hated the changes to tabs that were made. Is there any way I could install an older version of an apk? Same goes for Package Disabler.