I installed openSUSE 13.2 on my Acer C720 Chromebook about two years ago. It was a complicated procedure but it ran very well. Then someone trashed it by starting Chrome. One of our members suggested installing GalliumOS and I did but there were serious systemic errors. So I installed Lubuntu 16.04. It works, but I don’t like it. So I am considering going back to 13.2 but I am concerned about running an unsupported version with no updates. Could someone give me an idea of how dangerous that might be for malware? I use Thunderbird, Opera without Java, Firefox with Java but cleared at exit, and Wine running RS-DOS emulator running Microware OS-9, and pretty much nothing else.
You should be able to install the regular x64 LEAP or TW versions of openSUSE without any issues.
As for running any old, unsupported version of openSUSE… There are many unpatched vulnerabilities you’d be subject to, for instance the “Dirty Cow” kernel exploit of last year (2016).
If I may suggest, take the time and install 42.2 or Tumbleweed on the machine and see how it goes. I have a Chromebook with a Chroot Linux environment and it works well but I am real tempted to wipe and put openSUSE on it. If you do this, I would be real interested in your experiences.
I can recommend the Acer C720-2848 which is Celeron x64 2955U powered and sells for under $200 in the U.S. I am planning on buying a second one. It’s VERY fast. One shortcoming is the 16GB SSD. But plugging a bigger SSD in the slot solves that. The biggest problem I have had is people opening it and not following the large warning label I pasted on the keyboard. Instead of pressing CTL + L to start Linux they follow the ChromeOS instruction, press SPACE and all is lost. I am looking for a locking belt to protect it.