Fair Use to quote a translation in a commentary?

Hi... This is my first post here. I hope it's suitable to some extent. (I didn't see any livelier print-press forum with related topics. If you know of a more fitting forum, please let me know!)

I'm publishing a book that may end up online and will certainly be sold online. Anyway, the law might apply equally no matter how it's presented.

Our book is a commentary on a new translation of an old Russian novel. Our book is an interpretation of the novel. My author comments on each chapter as the book goes along. He quotes from the novel several times in each chapter. The quotes are generally a sentence or two long. I suppose he might sometimes even reference page numbers, or might like to.

The book is in effect a reader's guide to the other work, but with a twist, the extra view added by my author. It's not just a review of the novel. My author attempts to show how the classic novel can be read to shed light on life and to live better. Maybe you could say it's a self-help book built around a new translation of an old novel.

The novel is from the 1800's and is in the public domain. But the new translation would be protected, right? Or what?

I suppose the work in total is quoted 50 times.

We're thinking of going through and substituting quotes from an old public domain translation. It wouldn't be as good, or as current, but it's free for grabs.

So, what part of the old novel is actually public? The original Russian? I suppose only an edition from before 1930, or whatever date it is, is public, no matter what its content. So really the copyright of the translation is the only relevant fact. Right?

So we can't claim free'n'easy use of the new translation. And Fair Use is always up to a judge.

Ugh. It would be nice to use a translation that people would likely buy to read along with our book.

We have no budget or interest/time/skill in approaching the publisher to ask if we can quote from their translation. We also don't want to do business from a gray area. My experience is that businesspeople say No to this kind of thing. (Ha... My only other experiences involved notorious literary stars, so maybe not the best places to start asking for permission. But I've had other majorly huge publishers pay me for using excerpts of my properties in their textbooks and I was happy to cash their check. But a sentence isn't an excerpt, of course. Yet there's the cumulative effect of our book being created based on the other work.)

Ideas, feedback? Thanks! --JP