Who decides the casing of newly coined words?

Solution 1:

Site Pack isn't really a newly coined word, but the name of your product. Therefore you can choose whatever casing you like.

The design of your logo is also entirely up to you. There are many cases of companies whose logo is one case, but their chosen casing for the written text is different, for example Facebook and Twitter.

However, I'd advise to keep it simple and use Site Pack for both text and logo. Some companies can get away with things like iPlayer, but if you have different ways of writing it, people will sometimes get it wrong.