It will work, no matter how many channels you join at the same time, cuz the raw is only triggered at once, so it will be echoed to the correct channel, with each call.
That's because we are not doing /echo -a but /echo <#channel>
Regarding the statistics info, looks pretty straight forward I suppose: /help $nick and check out the aohvr parameters.
Just get the total ops, voices, regulars etc. and compare it to the total nicks in the channel.
Greets
