On the basis of what you've said, the package you've linked to seems fine to me. (I don't know anything about the company.) Have a look at the files you have for the site you've built, and see what the total file size is. HTML/CSS files are (should be!) pretty small, and you can keep down the size of your images by optimising them. If you're planning on allowing people to upload images to your message board, you should be able to set a maximum file size, to stop your disc space getting used up too quickly. If you do start to outgrow the package, you should be able to upgrade easily.
The specs also say "Host up to 6 websites on a single account", so I guess that answers your question about your second site.

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