Regarding neveilah (See Bechoros 23), there would be no distinction to be made if you were wearing a glove or you sat on a dead animal (though sitting on a pillow on TOP of the animal would be different). The conveyance of Tumas maga happens irrespective of your clothes, which are considered batel to your body.
The issue regarding yayn nesech is its use for sacrament. How would gloves interfere in any way with the non-Jews ability to use this wine? It doesn't. Which would mean that the wine is just as assur as if he touched it with his hands directly. After all, he's only indirectly handling the wine anyhow as it's in a bottle already...
I'm going to refrain from talking about niddah and using a derech chibbah glove ... :)
Never mind ... A person isn't even allowed to hand objects to their wife while she is in niddah (it's one of the harchakos) or sleeping in the same bed even if they aren't touching. Even more so is actually touching each other "through" an object not allowed.
If you're asking on a de'oraysa level with niddah, then answer this - can you touch her through her clothes while she's wearing them "derech chibbah?" Pretty sure that's a straight "no." A glove wouldn't be any different - it's just adding another layer to feeling each other. The Rambam makes clear that touching ANY niddah woman in a pleasurable manner is a d'oraysa violation, and one that may make you subject to malkus (machlokes on whether it's all women or only certain ones). (Issurei Bi'ah 21:1)
For muktzeh, we see that you are not allowed to lean up against a small tree since you are moving the branches by doing so. This is despite any clothes you may be wearing. That implies that the clothes aren't chotzetz - the issue is moving an object using a direct koach gavra, and gloves wouldn't solve that problem. We get around this issue on shabbos by moving with a shinui or indirectly by moving a permitted object, but we DON'T permit you to wrap your hand in a napkin and move the object normally.
Gloves in a mikvah WOULD constitute a chatzitzah because the standard we apply to tevilah is far and away more chamur than any other instance. Even though loose clothing would technically be permitted in a mikvah, the accepted practice is that even that is avoided. In general, the balance of halachic literature would seem to treat gloves, clothes, etc. as a default negiah lechumra but NOT lehakel (like in mikvah).
If anyone can think of a case where a gloved hand would be any different than either a) your hand touching a clothed body or b) your clothed body touching a bare object, please leave me a comment.