Concerning openSUSE: Check this web page out: https://en.opensuse.org/Portal:Distribution
Current releases listed are 13.2, 13.1, 12.3, Tumbleweed (rolling release), Evergreen (extended life releases)...
I tried 12.3 awhile ago, and although it worked on a CF-30, it was a pain (learning curve) to add touchscreen calibration.
I would have to download and try again, but I believe how you add software is not like how it's done with Zorin, Makulu, Mint, etc...
It uses YaST software management: https://en.opensuse.org/YaST_Software_Management
Concerning your security concerns (above), I would think any distribution that runs "live" on a usb that does NOT use persistence, meaning it does not save any information to the usb would work for browsing, etc.
CF-30 MK2 SSD LMDE2
Betsy, MK2 Navigatrix, Fundraiser for TbT
CF-52 GUN SSD LMDE2
Betsy(NICE) Thanks Sadlmkr
CF-29 MX-16 (https://mxlinux.org/
CF-28 MK3 MX-14.3 & MicroWattR8