You can't contest swords in the air, generally speaking. Air to air, the sword generally wins, as it has more range and a disjointed hitbox. There's some exceptions if you force them to start falling before you jump, but it's mostly safer to respect their sky stabbings. Shielding aerials and then grabbing, or jumping out of shield for Nair, is a much safer answer to their approaching aerials, though dashing back to contest their aerials after they begin to fall can still work (especially reverse aerial rushing a Bair). Fair is often a liability against swords, so try to either stick inside their range with Nair, if you must air-follow, or get below them for Uair / cross them up with Bair. Cloud, specifically, seems to have some problems punishing shield, outside of the rare limit neutral B, I suppose. In any case, Cloud charging limit for free obviously isn't great, but, unlike smash 4, it's not the end of the world, given it only lasts 15s. Most Clouds will have a specific use for limit that they rely on almost exclusively, so pay attention to how they use their first one. Other than that, the key is not to panic and stick to the ground when in doubt-- the less you jump against a swordie, the less their disjoint will matter. Use the soft throw splat bombs to cover approaches, don't forget about neutral B, lean heavily on Fsmashes as a punish (especially to punish landings if you can space them out with a dash dance), and remember that, once your in, Cloud doesn't really have an "out" other than trying to jump away, because his only space-making move tends to be Nair.