Forced tether hop animation is 50 frames long. When landing on stage they don't have to spend the whole animation airborne, but it's still some 30-40 frames depending on character, and then there's also 30 frames of landing lag. So yeah, there's time to react to their drift. On drift back, best option is ledgehop bair. On drift forwards you can do...pretty much anything. Best options are probably up angled fsmash if they're at kill percents, otherwise grab/dtilt/Flame Choke to start a combo.
What I spent some time labing was to see what options we have to cover all drift options, as that should allow for high consistency of punishing tethers due to only needing to react to the pull in. Of course there's the very obvious solution in uair, but that's a weak punish on drift in. What I came up with was ledgehop bair to cover the fade back, and then grabbing them if they drifted in (and then dthrow bair/uair/fair). The punish window is large enough that this can be done easily.
One of the problems with this is that the landing animations of Lucas, Toon Link and ZSS are low enough that
Ganon's grab can miss if you grab at the wrong time. It can also
whiff on Link/Samus if you're not quite close enough. Ivy's landing animation is very upright, so there's no worry there. While this is annoying, like I said the window to grab is very lenient, you don't need to grab right away. So you can simply wait past this point in their animation and then grab them. If you're really worried I supposed you could also dtilt.
Another problem is that dthrow is not particularly potent on Samus, the only aerial you're able to get past mid percents is uair, and that'll usually be the mid hit that won't send her particularly far, and then eventually we lose the ability to even land that. I think dthrow upB works until fairly late percents, so that's a pretty good option.
Other potential options for coverage that I haven't tested but should probably work out are a properly timed Flame Choke (possibly the best option against Samus, since AFC > Wiz Foot is a thing on her, or techase Wiz Foot if you get ground FC), or doing a short ledgedash then turnaround ftilt for fadeback or whatever you want for drift in.