Sorry, I was in a bit of a hurry as I wrote my first post. I simply forgot about Solaris, TBH.

The reality is a bit more complicated.
Torrent: The version now used in BP as Sanctus is only slightly altered from the normal version. Steve-O is reworking that model, last time I've heard from him, he was working on the turrets.
Tethis: First, it had most of it's small turrets removed and was adopted into BP as Narayana. Later, Esarai optimized it and gave it a new map. Steve-O didn't said anything about reworking it yet, but then, nobody asked him about it.
Hyperion: Ok, this one has quite a history. The very first version was included into original AoA release, already named Karuna. Then, Steve-O released a new version, which got adopted into AoA 3.6.10 and WiH. This one was used for a long time, undergoing tons of revisions and modifications. Like Narayana, it was also partially de-turreted. Recently, Esarai reworked the model once again, optimized it and gave it a new paint job. Independently, Steve-O started work on his own optimized Hyperion, which is currently WiP.
Vexor: This was the original Solaris. It didn't undergo many changes at first, but when Esarai joined, he showed us another, unrelated model which he was working on. At one point, it was decided that it will replace Solaris. The Vexor, which had some significant performance issues, was then dropped from WiH. Fast forward about a year (wow, it's been that long?), and Steve-O showcases the new revision of the Vexor (still WiP), beta of which is available to BP team for testing.
So, that's roughly the history of those ships in BP. Summing it up, if you want the original Steve-O's paintjob and armaments, you'd have to wait for the reworked versions. If you don't mind having BP-style textures, then you can use Esarai's versions of Tethis and Hyperion, you should get them from the latest version of WiH.