I'd say first of all that you're probably making this more difficult than it needs to be.
Movie studios aren't normally going to be interested in shutting down movie reviews. They want you to talk about their movies, and they want you to show clips from their movies -- so much so that many of them will simply add you to their press list just for asking.
If you ask to be put on their list of electronic press kits, the studios will proactively send you stills and clips for inclusion in your reviews. In that case, you're operating under a license from the studio, and there's no need for a fair-use inquiry.
But even if you can't get on to that list, it's pretty clear that what you're talking about would be fair use. You can read more about the standards for a full fair-use analysis here, but the key question in your situation is going to be whether the use is transformative, and it's pretty firmly established that commentary is transformative:
The central purpose of this investigation is to see, in Justice Story's words, whether the new work merely supersedes the objects of the original creation, or instead adds something new, with a further purpose or different character, altering the first with new expression, meaning, or message; it asks, in other words, whether and to what extent the new work is "transformative."
Although such transformative use is not absolutely necessary for a finding of fair use, the goal of copyright, to promote science and the arts, is generally furthered by the creation of transformative works. Such works thus lie at the heart of the fair use doctrine's guarantee of breathing space within the confines of copyright, and the more transformative the new work, the less will be the significance of other factors, like commercialism, that may weigh against a finding of fair use.
Campbell v. Acuff-Rose Music, Inc., 510 U.S. 569, 579 (1994). See also Video Pipeline, Inc. v. Buena Vista Home Entm't, Inc., 342 F.3d 191, 200 (3d Cir. 2003) ("The fact that a substantial portion, indeed almost all, of the infringing work was copied verbatim from the copyrighted work with no additional creative activity reveals a dearth of transformative character or purpose.").