I have a compatible dive computer, but yes, the transmitter is quite expensive. I need get other things first.
I only have options of MV, Rover, Proton (plastic). They also have Abyss Octopus, but its expensive.
From that list, depending on how expensive, I would lean towards the Abyss Octopus and consider it an investment.
In the future, you could always purchase a non-octo abyss cover for about 20 euros +/- , and have it tuned like the non-octo and have 2 really good performing 2nd stages.
Abyss Cover
All the 2nd stages you list are "good enough" as an octo, but the best investment would be the Abyss octo....you will appreciate having it if you decide to configure your reg set as "primary donate".
-Z