Were Rey's parents Force-sensitive?

Pending an explanation in some comic or novel, it’s unlikely an answer will ever be shown in film form.

The reason for this is that it’s entirely unimportant to the story. It explicitly stated that her parents were nobodies – well, they chose to be nobodies, for her safety. Since it appears being Force-sensitive indeed may have some connection with blood lineage and subsequent training to harness it, one can assume Palpatine’s kid(s) probably are Force-sensitive, much like the Skywalker lineage.

However, Palpatine’s goal was the plot of the movie Being John Malkovich. If this was the case, the body he intended to inhabit in the future needed to be Force-sensitive. Therefore, one could assume Palpatine’s kid was not Force-sensitive, and Rey was. Rey’s parents didn’t want to sacrifice her to her grandfather’s plot, and thus ran away and abandoned her on Jakku.

That would be a good argument that Palpatine’s kid was not Force-sensitive. But we probably will never know, since they didn’t even name the character. :/

The film very quickly shows a flashback (or Force vision) sequence of her parents and what happened to them, but nothing more.

During that flashback scene Kylo Ren has a voice-over and mentions that Rey's parents could have been great but instead they chose to be nobodies. IMO that's a hint to them at least being force-sensitive.

The way I interpret it is that Rey's parents didn't want themselves and/or Rey to join the Empire so instead the chose to run away and hide. If Rey's parents weren't force-sensitive I don't think Palpatine would have shown interest in tracking them down and/or have suspected that Rey herself would be force-sensitive.

I would argue yes even though it's not explicitly said because Palpatine sent Ochi, a jedi hunter to find them. This implies that Palpatine knew he would need someone experienced against force users to catch them because Ochi would have had experience catching or fighting force sensitive people.

While the jury is still out on Rey's mother, we now know thanks to The Rise of Skywalker Novelization that Rey's father was "powerless".

Paraphrased by Screen Rant

This passage in the book reveals after Return of the Jedi, Palpatine "thrust his consciousness" into a clone body. However, "the transfer was imperfect" and members of the Sith Eternal worked tirelessly to engineer a new vessel for Palpatine's essence. One of these attempts is described as "a useless, powerless failure" who was "a not-quite-identical clone." While this body wasn't fit to house Palpatine's power, it was still able to live and eventually became Rey's father.

It was recently revealed that Rey's father was a partial clone for Sidious to transfer his consciousness after Return of the Jedi, but this vessel was deemed "imperfect", "useless", and "powerless" by the Sith Eternal, but went on to live his life and eventually father Rey.

This implies that the reason that the vessel wasn't used was because he was not force-sensitive, something that Sidious/The Sith Eternal would need to succeed...