There are many Harry Potter RPGS (virtual games) out there. All you need to do is preform a search.
Yes, there are many Harry Potter RPG's online.
Most any bookstore or even on websites. Harry potter is a pretty big series, so most any where.
Well there's Pottermore for a start.
Pottermore and muggle net interactive
No Harry Potter doesn't have any sibling's.
Ebay or amazon sell Harry Potter stuff there is a lot on theose websites: www.eBay.com or if you are from the UK go on www.eBay.co.UK www.amazon.com
Harry Potter does not have any brothers or sisters.
No, only the Basilisk in Harry Potter is in the second book/movie Harry Potter and the Chamber of Secrets.
There is no janitor in Harry Potter at any time.
Harry Potter will appear in the Harry Potter books. If he was to appear in any other published novel it would violate copyright.
No, nor was she in any of the Harry Potter movies.
No, Toby Hemingway is not in any of the Harry Potter films.