In terms of micro buggies...everything you've mentioned except the RC18 is a bit out of date I think.
The scales have all gotten a little muddled these days, with people calling them 18th/16th/14th etc etc, but really they are all much the same.
In terms of cars that are raced and supported for parts etc, then look at the Carisma cars...the GT14B or the new GTB is coming soon. Losi do the mini 8. Schumacher have just started importing selling something too, so that could be worth looking into.
All those, plus the RC18, are all currently being manufactured, so have parts support. The Carisma and mini 8 both come in RTR form I think, which could suit your daughter.
The RC18 is not really very active as a race car though, the Carisma and Losi are much more popular for club racing, more robust, easier to drive, better supported, etc, etc.
Check out this other forum....
http://www.uk-microrc.co.uk/forum/index.php?
...for more info on micro stuff!