"I flew on Islanders in Philippines, as SLF - there are a lot there."
There were a number of Islanders assembled in the Philippines by Philippine Aerospace Development Corp/PADC with a number of parts locally manufactured.
Engine start cycles is a spurious arguement against the Twin Otter - the cost of PT6A-27/34 cycle limited components is around $2 - $3 per start cycle, per engine. Battery recycling and hot starts is a far higher risk on very short haul cycles. Ground power, if available, is the solution.
I don't recall a prop brake ever being an option on the Twin Otter.
Excluding capital costs, the DHC6 demonstrates far lower seat/mile costs than a Trislander.
There was
rumoured to be a number (12?) of new Trislander airframes in Australia, reputedly the intention was to install V8 engines but it never happened. I also saw a "long nose" Islander in Australia, no idea what happened to it.
From my experiences with the BN2A Mk III Trislander, they were Britain's revenge on the Empire. May they rust in peace!
70 year old DC3/C47 belong in museums, not in commercial flying operations.