Those dropouts will work perfect. You will not need to use the old derailleur for chain tension.
You will not have any problems with the dropouts.
These articles might be of worth to do a quick read:
http://sheldonbrown.com/fixed-conversion.html
http://sheldonbrown.com/deakins/how-...onversion.html
You probably have a good idea of what it takes to do a conversion, but, hey, you might learn something new.