JQ> Is it possible to access fidonet over nntp? 

yes, but it isn't "FIDONET"... it is whatever messages the BBS you are
accessing has decided to offer via NNTP...

fidonet echos are not available on the general usenet groups...

 JQ> If so under which hierarchy  do they reside in?

that depends on the BBS you are using...

)\/(ark

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