#1
can we mic all the instruments and vocals directly in the console then plug a 4track and record all the sounds on one track?
#2
Sure but its not the best way to do it...
Your goal in recording is to record each instrument on its own track, that way if you have a part you want to add reverb to, (like vocals) or if you must adjust the level of one instrument in editing you can.

Once they are all mixed down to a single stereo track its next to impossible to edit each part so you better get it right the first time.......

BTW this "console" you are talking about is a mixer...just so nobody is confused about it.