Here's a rundown of some options on the table
Fox 1 upthrows
Fox 2 is DIing to where he will hit the platform near the lip at the center of the stage
Fox 1 waits for a tech option and gets a reaction upair combo
Another version of this
Fox 1 upthrows
Fox 2 is DIing to where he will hit the platform near the lip at the center of the stage
Fox 1 waits for a tech option
Fox 2 techs in place and Fox 1 misses his opportunity to punish because he has to read that tech in place in order to punish it, usually with an upair
And then we add another layer
Fox 1 upthrows
Fox 2 is DIing to where he will hit the platform near the lip at the center of the stage
Fox 1 reads a tech in place by preemptively attacking Fox 2's landing spot on platform
Fox 2 techs in place trying to read that Fox 1 will wait for a reaction like most foxes do
Fox 1 gets the second hit upair if Fox 2 techs in place or misses tech
If Fox 2 doesn't tech in place and you land like this, then you can still guard center from this position
I've noticed that some people will miss tech and SDI your first hit upair off the platform if your (fox 1)'s momentum is going out rather than in, so instead of the upair here you can do a bair for more guaranteed % for a smaller punish, unless it gets them off stage.
I know Hax likes to waveland, react with shine if they tech in place, uptilt if they tech toward him, and I think the next depends on if the option to tech away is to the inner part of the platform or the outer part, but my guess would be inner -> sh upair, grab or upsmash, and outer -> nair or pivot shield drop bair, sh upair.