[@Dreaming]
As far as roles go, it'll depend on how you customize your FRAME within the RP. There will be a number of ways to fit weapons onto the machines within their allocated weight/power ratio. Most FRAMEs will have a relatively balanced set of armaments - say, an autocannon, AT missile launcher and anti-personnel machinegun. But there are many variations you could take; maybe two missile pods and a lighter gun, or even a number of autocannons, or larger tank-sized cannons. It'll mostly depend on what's available to you, but strictly speaking, roles will come into play on a per-mission basis.