Because they traded technology
From the Memory-Alpha write-up for TOS: The Enterprise Incident
Kirk then inexplicably orders helmsman Sulu to take the Enterprise
across the Romulan Neutral Zone and into Romulan space, where it is
quickly surrounded by the Romulans – who are now using Klingon-style
An effective cloaking device, meanwhile, ...
In a word, no (or possibly maybe). Admiral Nechayev is certainly adamant (in TNG: Descent) that should the opportunity present itself again to commit genocide that Picard should take it. I think it's reasonable to assume she means by using the geometry-virus but isn't limiting her order to just that one method.
NECHAYEV: Your priority is to ...
I just found this place and I think I can help you all out a little bit. In Star Trek: Enterprise the United Earth was established, in the time of the Enterprise Series.
The United Earth founded Starfleet and the security council, this is part of the local planetary government of Earth and is Starfleet is the military science branch of United Earth. The ...
There's no specific confirmation in any of the TV shows, films or official novelisations whether (or not) Romulans have a Katra. Their general lack of telepathic abilities would suggest that they don't have the ability to use them to transfer knowledge, but then again, who knows what goes on at the highest echelons of Romulan society or behind ...
All living beings have a Katra.
But @Valorum's answer is correct - there's no evidence that Romulans are aware of it, or can "use" it.
In Star Trek: Discovery S01E06, Lieutenant Stamets explains his understanding of the Katra concept:
STAMETS: I got to say, this Katra stuff is way cool. An uncharted superhighway connecting all of conciousness and life?
Data frequently "gets it wrong" when repeating quotes and imitating human behaviour.
Throughout The Next Generation TV series and movies, Data imitates examples of human behaviour that he has observed. He often misunderstands the original context of these behaviours, making his reenactments misguided and inappropriate.
Growing a beard similar ...