No character, just use a ";" between the commands.  eg

alias +cjump "+jump; +duck; walk_off"

Hmm, I haven't tried to bind to keys hit, but it may work.  The way I
would do what you want is to find out the actual commands the "P", "2",
and "1" key sequence is executing and bind those commands.

So to directly answer your question, try:

bind F9 "p; 2; 1"

to use the F9 key to achieve what you want.  I have no idea if this
works or not, and leave it to you to test.  If it doesn't work at first,
try putting some "wait" commands between the above before giving up.
YOu might need several.

As I said, I would do it like this:

bind F9 "ma_slapmenu"

That command name is just made up, I don't know the command exactly -
you might need to search for it.

look at

http://www.mani-admin-plugin.com/mani_admin_plugin/documentation/mani_admin_plug
in.html

for commands.

bind k "ma_say There will be no... ; ma_say This is the one and only
..."