Get it surveyed by a licenced engineer before parting with any cash it could save you a fortune.
Looking at the list, one Tomahawk does not show the airframe hours and they are lifted on the wings.
The other engine is past TBO but as said can be flown on, but that is an engine rebuild in waiting and that could cost you nearly as much as the aircraft, remember overhaul life is 12 years plus extension as with the hours.
The Arrow is also half share and as such you have to take into account his usage, they are expensive to maintain compared to a fixed gear none Autopilot aircraft..
The Rally has a RR engine in it which are getting difficult to get parts for, not sure on Continental compatibility, the 240 he mentions having you would struggle with parts.
Whilst I can see you saying its cheaper to run, if your in to this for the long haul then remember you need to factor in costs for the engine overhaul you will end up needing, and parts like mag overhauls every 500 hours (do not know NZ requirements) plus checks and any other parts.
Which brings me back to paragraph 1