There are lot's of variables that affect the displaying of ranking on the SERPs, some of them include location, account settings and many other things. Google also runs tests on their search results constantly so you might see some variation from that as well.

What does all this mean? Don't worry about the details so much but look at the overall trend to see if in general your rankings are going up or down. If you are tracking rankings manually i would use the same browser using the same settings each time to check the rankings, this you will use as your baseline. Then you will be able to monitor for any changes in rankings based on these set variables. If you then check other browsers you should see the same general trend even though the results may not be exact.

It depends on what your purpose is.

If you want them totally block from being index then putting the page in the robots.tx fil or using a robots meta tag would work fine.

If you just want to de-emphasize the page to the search engines you can use nofollows or javascript links on footer/header links.

One thing that we have done is to combine some of these pages (terms and privacy) into one page to cut down on the number of total links on each page.

You could also not include the privacy page link on every page (depending on your site) but just link it from certain pages that collect sensitive data (near the form).

I hope this helps. The main thing to remember is that each site is different so you will have to adjust your tactics depending on precisely what you are trying to accomplish.