Some of the UFO's are available through regular 
channels, but a lot of the plushies are items 
that you get from mailing in to Hana to Yume (is 
it called zennin? furoku?)

The UFO catchers on the left-hand side are 
definitely items that are normally available. 
http://www.ufocatcher.net/ufoplush/fruits/main.htm
l

I don't know about the Kyo-in-the-cat-suit on the 
right-hand side. But I do know there are people 
who make custom plushies, so you might try to 
make contact with one of them to do a replica, or 
even do other characters on the same theme.

You can see some of the (zennin? furoku?) items 
on this page, though:
http://home2.pacific.net.sg/~chiang0809/Sale/doll-
fb.html

I don't think it's exhaustive, but it's a good 
start to see the range of items available.

-Cres