Well, if replacment of the Cessna's is next on the list then assuming the role of said aircraft is basic training, observation, hour building, para training why not just new cessna's.
Or if you're adventurous, then a mix of PC-6's and BN 2's or Defenders.
The mix gives single and twin engine training options, plus good options for para training (aswell as towing targets) and both are robust aircraft with felixibility. Both are high wing for observation, both have STOL.
Just a thought.
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