First off, Google encourages nofollow links for when they apply. They are not going to beat you up for following their recommendations.
There is a bit of a conflict here:
Google at one point flat-out said not to make links in footers to other sites. However, on the other hand it also said that it is reasonable that a company would want to link brand sites back to the parent company and therefore will not punish these sites as long as they are reasonable in their actions. Google is only concerned with links that are unnatural and not a reasonable thing to do.
The webmaster guidelines says:
Widely distributed links in the footers or templates of various sites.
This applies to link schemes designed to build authority in a manipulative way. You are not doing this. In fact you are doing a reasonable thing.
Google uses semantics almost throughout it's entire operation. As part of this, it creates clusters (semantics term) that ties sites into relationships as well as brands, contact information, and so on. With this, Google can see that you are linking to a "terms and conditions" page from your brand and product sites rather than copying the page on multiple sites. This is a reasonable thing to do and Google can see this.
You are worrying too much.
You are doing something that is reasonable and normal within the web. This is your right to do. If you change these links to nofollow, this is also a reasonable thing to do and also your right to do. Google does not make the rules on the web and must work within the same set of rules that applies to all of us. If you are manipulating search by building authority in an unnatural way, then Google has the right to ignore your site. But if you are being reasonable and doing what is a reasonable thing to do, then Google would be foolish to punish your site.
