#1 I usually make my own favorites list but I'm sure there are identifier's to get the channel names from your mIRC favorites list.
#2
I would make an alias and do these things.
alias knekt {
;$1 = server, $2 = channel
Check for connection to $1 (server).
if connection exists, /scon or /scid to connection, join $2- else { server -m $1 -jn $2 } (connect to server & join $2)
}
You need to read about /scid $scid, /scon $scon & /server.
Then you would just call the knekt alias in your popup.
menu menubar,status {
Knekt:knekt $?="Enter Server Address" $?="Enter Channel Name"
}
That's the basics. If you need to authorize you will need to wait for the auth request from the server then reply with the proper information.