No worries about the shrimp, there are plenty more. As for the Val's, I have dosed Excel before. I followed the protocol as described with the following caveat:
I have a 75 gallon tank with a bunch of wood so I 'guessed' I had 60 gallons of water. I have never actually measured it.
All in all, this looks to be an effective treatment as long as you don't mind some casualties along the way. All my fish look great, no deaths there. To me shrimp are a little more expendable but YMMV.
Sorry to hear about the cherry. Hopefully there will be no more deaths. Though I'd consider even one death to be an indication they may need to be treated as a special case, with reduced dosage.
The vals aren't a big surprise, as they're notably sensitive to Excel. Were your vals already pre-acclimated to Excel, or is this their first recent exposure? Which Excel dosage did you use?
Looking forward to further updates.