Why don't you use the native Linux version of REAPER? Just download it from Landoleet!
Linux will probably be officially supported starting with REAPER 6. BTW, ARA will also be supported then (but that's irrelevant for Linux users as long as Celemony and others don't port their tools to Linux).
Ardour/Mixbus have become pretty stable too. I'm using Mixbus 32c 4.3, and if/when I'm on Linux, I don't use any Windows VST plugins at all, just native Linux stuff.
I also have Tracktion T7, but I never use it. The GUI is not my cup of tea, and it has no real mixer (Waveform, the successor of T7, does have a separate mixer, but that DAW is still way too stoneage for me).
You may also want to try Bitwig. Not my cup of tea either, but ymmv.
I use UbuntuStudio 16.04, but installed some additional software (basically the KXStudio stuff, to try out Carla).
I paid for the Overtone DSP Linux plugins, and I use the U-HE Linux ports plus some freeware plugins.
Nowhere remotely comparable to the endless options you have with Windows (or Mac), of course, but you definitely can mix and produce on Linux - well recorded tracks assumed.