Jab is kind of like your new downtilt in neutral, almost. The difference is, it's awful vs CC and usually not as safe for pressure. It's better at dealing with short hops in the neutral, however, and has better ability to lead into combos. The other dtilt replacement is shine, which has much worse range, but can actually deal with CC (if you don't get hit first) sends them away, and you have guaranteed followups out of it. You can't really AC nair jab dtilt wall, the closest thing you have for walling is bair, which means turning your back. Nair to nair to nair to nair to....... or something other than nair is a combo that works on the entire cast, be wary of CC though. Uair chains also work on everyone. You have better OoS from behind in the form of bair, and when closer shine OoS. Usmash is an OoS option with more comparable range to grab, but is less royzonable, hits one frame later (because jumpsquat), doesn't hit people shielding, triggers counters, and can hit lower limbs (unlike grab). Upthrow into juggle and cause pain still works, and has faster payoff, but can't necessarily be spaced as easily when it doesn't truely combo. Other throws -> tech-chase aren't as easy. JC grab is still flipping amazing, you have a projectile now, so work on using it. You no longer get forced to approach.
Nair is better for actually approaching, and not just hitting someone trying to approach. Try to avoid super early nairs in shorthop at part of an approach, you could have done something other than nair that would be better in those situations. Low aerials are key when the opponent's also on the ground... Mostly. Grab ledge->DJ bair at various heights (and preferably always doing so so that you can autocancel when they're recovering from higher, and to cover as many low options as possible + somewhat above the ledge when from lower) is effective in edgeguarding pretty much everyone. Against other fastfallers, fsmash and fulljump bair can deal with almost every recovery option. Dsmash at the ledge, if hit, is devestating. If they might go to the ledge, down angled ftilt and ramen noodle are relatively easy to use. SH bair from onstage when covering grabbing the ledge and slightly above it tends to work pretty well if you want to avoid a hitbox from the third jump. If you have more time, your fast fallspeed allows you to short hop, or even fulljump backwards onto the ledge to deal with recoveries like Roy's and Peach's that are sufficiently close to the ledge horizontally that they have to hit through the stage, and grab ledge before they have any chance, whilst completely avoiding the hitbox.
Still try to stay grounded, getting hit out of your jump isn't fun, and you have poor aerial acceleration and speed. You jump direction is very committal even if airtime is short. Ftilt isn't very appreciated in neutral, but it's better against characters with bad dashdances and ones with low traction. You could also just dashdance camp, but against characters with really good wavedashes, this could be more stressful. Platform camping vs. most of the cast tends to be effective, and not overly difficult. You're still amazing on FD, even if a lot of characters might chaingrab you or combo you vertically. You're still less vulnerable to the type that just pop the thrown character next to the opponent, the more horizontally based ones, and jabs as combo extenders (and similar types of weaker moves). FD is good because it makes everyone else's neutral much more linear than yours, relatively speaking, even if it makes camping harder. A lot of players or characters may try to hit you out of the Mozilla (Fire Fox) startup from farther away. If they attempt this by jumping offstage at you, illusioning at a height that avoids their move usually works. Most people won't cover a tremendous number of options this way, and you can react to attempts of this a lot of the time (or shinestall). If you side-b back or shinestall, you can turn the situation around, and potentially KO them for it. Aerials near the ledge at lower percents can mean fairly easy shinespikes off stage, and dsmash at the ledge can set up for one or easy edgehog and other option coverage. Illusioning higher can cause a lot of edgeguards using move from onstage to clank with the projectile hitbox, but illusion has a lot of lag compared to Fire Fox.
Spotdodge/getup shine can be a get out of jail card (or shine in general) but try not to rely on it too much. The opponent can space around shine with dashdances and shieldstop among other things. Of course, you can hit them out of some of this with jab (only one frame slower but more range infront) or even a smash attack can work.
In general, maintain stage control and try to play calm. Most people will be scared into panic options against Fox. Even if they aren't you can punish a lack of action pretty well too.
While a lot of people, especially in the current meta will try to crouch cancel you, they probably have worse tools for dealing with it than you, and you have pretty painful options out of it too.
Your moves have great hitboxes and have active frames now. It's much easier to challenge positions and attacks, and you're usually less likely to whiff when one or more character(s) is/are moving.
