#untap step

[magicjudge]

If I'm running a kruphix edh deck and have a seedborn muse and a copy. Can I respond after the fist trigger and tap my land before they untap again?

Seedborn Muse’s ability isn’t a triggered ability. It’s a static ability that modifies what happens during other players’ untap steps. As such, there’s nothing to respond to and no way to take advantage of multiple Seedborn Muses this way.

(Also, players never get priority in the untap step anyway.)

[magicjudge]

How exactly does Hokori, Dust Drinker and Seedborn Muse interact?

There’s no interaction between these two cards. Their abilities function at different times, so there’s no conflict.

Hokori will keep you from untapping your lands in your own untap step. Seedborn Muse will untap all your permanents in each other player’s untap step. They each do their own thing and never the twain shall meet.