If your jumps are spaced well enough, I don't think you really have to worry about it that much. I don't think the double jump is all that risky vs falco because he really is an up to down comboer instead of a left to right one. You'll eventually hit the ground and get your jump back, just have to be ready to tech. Falco falls so fast that if you full jump with Marth you are guaranteed to be coming down on him while he is on the ground. Usually to some sort of missed laser, etc.
As far as puff goes, the key for Marth is actually 2 things. Spacing as with -every- matchup, and patience (specifically within shield). I suppose you can throw in good OoS options, but I've played a planking Jiggs, a camping Jiggs, and an aggressive Jiggs. It's all the same I think. I love to shield, wait for the Jiggs to hold down to try to bait a shieldgrab so they can rest, then just wave dashing back and forward smashing. Too good.
I'm not saying Never fool jump. I just think constantly fool jumping will get you caught vs a few characters that are able to take advantage of it. Vs Puff....what you say sounds good but vs good/gay puff it is a bit more difficult to pull off. However it's all you can do.