All of those options are weird.
A Vekoma SFC with a mini launch at the start?
A Premier inverted Boomerang?
A Gerstlauer high speed invert with a vertical lift?
Watching that video, the SFC seemed like the one which would fit the park most. It's a suitable step between the park's existing coasters, albeit more on the tamer side.
The Premier also fits that bit I'd say. It has the extra quirk of going backwards, which also ups the thrill. I quite like the layout too, but it does feel like it goes on for quite a while (so could cause nausea with the backwards stuff)
The Gerstlauer one is definitely the most thrilling option, and I have a level of morbid curiosity about it. I'm not sure it's quite what Slagharen needs though; it comes across quite intimidating, when they need something a bit more approachable imo