Volare
Yes a new cargo ship contract has been agreed but on a very much reduced schedule to that provided by RMS St Helena and one which would not work for fresh foods , perishables and urgent items . They are looking at keeping the RMS SHL in service for longer but that costs money and the cost savings on the regular RMS service were part of the airport financial justification.
Smaller aircraft as you suggest are ok from a passenegr point of view, I think the Comairs were passenger load restricted anyway but the lack of freight capability has significant economic impact