Frontline safety in multiple-dog household?

Factual Questions
1

Frontline Plus (r) is applied between the shoulder blades specifically to keep the dog from licking/mouthing it directly.

We have two dogs now, who lick/mouth/playbite all the time, even between the shoulder blades.

According to Frontline’s official site, we are to wait 24 hours “until site appears dry” before bathing the dog.

It also says not to allow them into watercourses for 48 hours – somewhere I read “to avoid adversely affecting aquatic life.” Would wastewater affect wildlife if we bathed them in the tub within that 48-hour limit?

A vet site says “Ensure that treated animals do not groom each other after treatment until dry.”

We treated both dogs lat night. Do we have to keep them from physical contact with each other for 24 hours? 48 hours?

Can we bathe them (to remove superficial Frontline contamination on the fur) now? Should we wait 24 hours? 48 hours?

It’ll be a big pain in the neck to keep them separate; I’d like to restore normal activities ASAP, but I don’t want to poison my doggies or the aquatic wildlife.

One of the dogs is showing some slicked area of fur on her shoulder/flank that looks like the Frontline ran down her fur superfically a bit (blame me for applying it badly, I guess!)

Thanks for any light anyone can shed on this (no pun intended)!

Sailboat

2

…And if we do bathe them today (i.e., in less than 24 hours after application) will the bath make it safe for people to touch their backs and for them to roughhouse today?

Sailboat

3

We bathe our dogs in the bathtub, so the wastewater is treated. If you bathe them outside, you might just want to wait longer.
As for keeping them seperate, I think you just need to keep an eye on them and stop them if they start to lick the area excessively. It’s applied at that spot to keep them from removing it before it is dispersed over the skin, not to keep them from ingesting bad stuff.