Look at 50 USCS § 1809. It doesn’t actually say it’s a felony, but it says 5 years in jail. I think generally more than 1 year in jail is considered a felony.
Unmasking, without more, is not a crime. Illegal targeting can be, and maybe Rice is guilty of that, but I think she's on pretty solid ground if the search requests are for "communications of [Russian]".
She's going to hide in those "unmasking" weeds. I'd flush her out with the "discloses or uses information" crime, leaking the "dirt" is a felony.