How long should I wait between grout application and sealant?
According to the sealant data sheet, you can seal new grout after 48 hours.

For me I would play it safe if I could (do you have to be able to use this bathroom?), if the grout says no water for 7 days I would wait that long before sealing.  That is probably overly cautious but then I don't get much work done during the week anyway so for me waiting until the next weekend is not a big deal.

After sealing I would wait 24 hours before getting it wet.