If I own domain.com domain.net and domain.info I should to develop domain.net and domain.info because it will rank my .com higher?
^^ No. That is not what he was saying. If someone (your competitor) already owns orange.com, and you buy orange.net/orange.org and build up a site, then the person that owns the .com would get a percentage of your business, because of the natural type in traffic; traffic that was possibly even looking for your site to begin with. Or, you would simply just lose that traffic from the beginning. If YOU own the .com/.net/.org, then you can develop any one that you wish and redirect the rest to your site. However, even in this situation, it is still almost always best to develop the .com.
What if the OP used 'fluffy-kitty.com' instead of 'kittyfluffy.com'? That way he could get the domain and still keep the words in the right order. If his target keyword is 'fluffy kitty' then it seems to me it would hurt him to swap the words around. Other possibilities: fluffy_kitty.com myfluffykitty.com These might be viable alternatives as well, don't you think?