Hope this is the right forum - addon domain question

Hi all - I'm new here and new to making websites etc (about 3 months at it).
My question is -

I have a hosting package with bluehost - 1 main account and 5 addon domains. The first site I built when I was very new (main account site) was a total failure, but I kept it live just in case while I built a few more.
I began concentrating on one site which I want to turn into an authority site - its up to around 110 posts and had quite good traffic building from google until-

I decided to turn my main account site (first site I built) into a review site a few days ago, and while i'm building it I've disallowed search engines (using wordpress settings).
Since then my other sites seem to have taken a drop in traffic from google - i'm still getting hits from yahoo and bing.

So on to the question (finally!) I've been looking into what addon domains are, and am I right in thinking they are just sub domains of my main account? So if I've turned off google access to my main site will my other sites be affected?

Webmaster tools shows a critical error on my main account site (because I've disallowed google access) but my other sites are showing as ok.

I have a couple of outbound links on the site I've turned off pointing towards the site I'm building into an authority site and also wonderd if now google has connected the two?

I hope my question(s) make sense - it doesn't read very well but hopefully somebody will understand!
many thanks!