I wouldn't call occam's razor an explicit part of reductionism. It's basically equivalent to saying you can't just make up information.
I don't think so. This may be the case when your hypotheses are something like "A" and "A v B" but if your hypotheses you are comparing are "A" and "C ^ D ^ E" this sort of summary of Occam's razor seems to be insufficient.
If both hypotheses explain some set of data, I've usually been able to make a direct comparison even in what look like tough cases by following the information in the data - what sort of process generates it, etc. Keeping things in terms of the "language" of the data is in fact also justified by the idea that pulling information from nowhere is bad.
This sort of reliance on our observations is certainly an empiricist assumption, but I don't think a reductionist one.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
If continuing the discussion becomes impractical, that means you win at open threads; a celebratory top-level post on the topic is traditional.