So, it's come to my attention that I am severely lacking in this department. Which, as a Link player, is a pretty big problem. Any tips on not getting rag dolled by Mario/Wolf/Wario/Falcon/etc
Falcon in particular, if you can DI knee on reaction it gets waaaay easier. But DI uairs hard away and knee hard up and in past 70%, but if you're going cross-stage, DI the knee straight away to maximize the distance you fly until about 90% [Falcon can double knee us].
Here's the real secret to DI offstage vs Falcon at low percents: If Falcon has to use his double jump to hit the next aerial [he's below you where uair doesn't look like it'll reach], DI hard up and in [survival DI], as he shouldn't be able to hit you again. If he hasn't used his double jump yet, you have to DI away unless you're 100% sure knee is coming [and if you're so sure, it's probably because you're dead anyway, so don't DI it]. I myself still mess this up [more like I rarely get it], but uair -> knee offstage will kill you super early if you survival DI the uair, as that combos into knee, but if you DI the uair away at 50%, you won't die [unless it's like Yoshi's or some place really tiny] but Falcon won't be able to get his knee without SDing and therefore won't go for it.
Once you get to like 130%+ you can just survival DI the uair/knee mixup [at that percent uair should be launching you high enough to not combo into knee], but it's unlikely you'll reach that percent. Note that even at those percents, things like weak knee to strong knee will combo on survival DI, but you just straight up die if you combo DI a uair at that percent. When you get grabbed at super high percents, you have to guess if he'll dthrow or uthrow - on uthrow, at high enough percents you go so high he can't even uair [I'm talking the ridiculous percents like 170], but if you do this DI on dthrow you just get uair'd or knee'd and die, while if you DI away on uthrow it's easy to uair you, but if he dthrows you he struggles to followup with anything but a tech chase. Fthrow/bthrow can also kill if you DI for dthrow so... good luck?
The short of it: DI against Falcon is just really hard.
I don't have nearly as much specific advice for the others because I play them less. I can do something on some specific Wario situations if you want but I know little about the others.