i was talking about this with a friend last night. We both agreed that the best two beginning characters are sheik and Marth. the reason these two are the best are not just b/c u can spam moves and beat your noob friends but b/c they are the best at teaching you how to play ssbm. Marth teaches the importance of the grab game, and spacing if you want those tippers. Also his wavedash may not be the easiest to use /learn with but its very useful. Marth also will help noobs learn how to tilt starting with the easy to use down tilt to the harder for beginners up tilt, and u need to use marths up-tilt since his up-smash is pretty bad.
Next is sheik. She also helps people learn how to tilt and to not spam smashers. she also has a great grab game and with down throw will help people learn chain grabs and tech chasing. Her less then great recovery will get new players to learn how to be trickier while recovering which is important. She also helps people get use to gimping. Lastly her easy combos help people visually see what can or can not combo and overall this helps people get a feel for the game.
So i thunk learning these two are better then jiggs for a beginner if they really want to learn to get better and play smash