Is it advisable to emphasize (italicize) good research qualities in a research statement?
The preferred details for typesetting your research statement are likely to be highly subjective. Different things are likely to be pleasing, striking, or off-putting, depending on the individual preferences of whoever is reading your application.

I would agree that italics are one of the preferred methods to provide emphasis without being too flashy or distracting. Whether or not that is the appropriate choice for your research statement should probably depend to some extent on the style and content of the rest of your application as well. If you have access to a university writing center, you should try to speak with someone there to decide on the style and arrangement of your application.

To speak to my own experience, I generally will not consider a candidate more capable or skilled in independent thought, rigorous work, or attention to detail, because it is typographically emphasized on their application.