As a player who secondaries Jigglypuff myself, I suggest you use more shorthop laser cancels. Against Falcos who rarely spam lasers, I feel much more free to do what I want, but against those who do, I start to feel totally boxed in!
Not that you should just spam lasers and only lasers over and over, then of course you'll start to become predictable. And not only the shorhops either cuz it will become easy to just float over there and rest on top of you. Try to constantly vary your altitude when firing, keep them guessing.
Know that a Jigglypuff is usually after one thing- that precious rest hit! A Puff is always going to be fishing for grabs at low percents, and uair/nair combos into rest at later percents, their going to be aircamping when you're on a platform or something, waiting to read your roll- a get up attack usually foils this if they come in to early, but it can also work against you as well if they read it and hover over you until it ends. Aircamping is annoying, but know that Puffs staying in the air with constant bairs aren't really trying to approach you either until you start commit to something, that's when they feel safe. So use that aircamping against by stopping their momentum with more lasers. If you know what they are after and exactly when they are after it, you can start using this against them. Puffs like to stay under you, that's their favorite place besides being off the edge with you. When Falco's decide to fall with nair after doing something in the air I was planning on punishing them for, I really hate it. And when they under me it's the worst.. nair/dair and my falling speed do nothing for me and I cant crouch cancel so try to be at the place opposite of where the Puff wants you- be underneath the Puff instead of the Puff being underneath you and you will find it much more easier to approach. A lame puff who wastes to many jumps aircamping will end up allowing you underneath them far too often..
Another good strat is counterpicking FD if you really wanna go that route, lack of plats really hurt some Puff players~