Yeesh
And as a DM, I would judge that a rule to trump another rule only applies to the rules that are specifically mentioned in its description. To assume other rules are also to be trumped, is still an assumption, and therefore should not be used as a core rule. A badly worded rule does not give any more abilities than what is written. Any assumptions or additions are houserules IMO. >

~ This is especially true for league play or RPGA play, as there should be a baseline that commonwealth campaigns must prescribe to.
There are so many grammar problems in 3.0 and 3.5 where rules are not written well or codified properly. The books aren't perfect, true. It just isn't possible. And in the past FAQ's and Sage Advice
tried to stick to the baseline of "If it doesn't specifically state it, it doesn't apply." That practice isn't perfect either, but it's probably the most commonly supported way to adjudicate most rulings.
Therefore in closing, I would rule that a successful use of a skill that pits wit vs wit (in the form of feinting in combat) is not trumped by Uncanny Frogs.
Of course, if they choose to amend the Uncanny Frogs rule by including feinting in combat in the list of things it protects against, I would accept that ruling as well. And I would debate why it would make sense.

But as of right now, there is something wrong with the idea of two powerful rogues dueling for power in a thieves guild duking it out like fighters. No bluffing and feinting with the wit and panache that comes with it. No mind games and getting the drop on the other guy. It's all about smack-talk and higher ground and who can slug it out best. Bleh.
....wannabe rogue who must match wits with his equals, rather than match brawn. (After all, I'm a skinny cutter trying to make my way outta the gutter, berk. Yer just in the way... Now I don't think I can take ya right here and now ye slackjawed sod, but that huge gelugon Mercykiller behind you might just do my job for me. *wince* Oh! Did my shiv stick itself in your ear? Sorry, but it must suck to be you, berk. Shoulda never made a mark of a Sigilan native. You cutpurses from the Prime really are clueless....)