PA - A few options, not necessarily four types.
One way to go is high-end ASW/MPA + a smaller type (bizjet or regional prop-based) for the herring-thieves and smugglers. Saab will tell you that an AEW&C can double up for useful wide-area overwater surveillance, which might be a useful option.
IAI-Elta, meanwhile, have a separate ASW option but then offer AWACS, ground surveillance and SIGINT on a common platform (Gulfstream) with similar datalinks and workstations.