[Honey]

toreduce high latency is to keep the gameserver "mods or plugins" as minimal posible.
latency realy depends on your specs and network speed.

No, mods or plugins do not use your internet, and don't make your ping higher, it may decrease your FPS but not your ping.

mods or plugins does use internet.
dynmap (minecraft plugin uses internet)

ah, Dynmap is connected to the internet as what it does is, display your minecraft map on your browser. your right that some mods may use internet but most of them only use internet because they have some sort of connectivity from browsers, most mods do not require internet speed but use server resources ( same goes for minecraft as the more mods you use the high RAM is required )