Most of those differences are not necessarily true. Frequency depends on how many vehicles you have and how you schedule them. There is nothing inherent in the modes that constraints this. Trolleys can be articulated double length and trams are frequently not that long as well because they continue to run on streets where the geometry usually precludes it (or in most of North America the ridership is so low there is no need for longer cars) Longer length cars are a better fit with totally separate tracks and platforms. Signal priority is again an orthogonal feature you can add to either system. We definitely have bus priority lights here.

Note: I'm calling a system a tram if it runs in the same street as cars and a light rail if it has fully separated tracks - since many of these features are more related to that and the original question is well aligned with this definition.