Hi, a nice pair of goblets, a lucky find there! As you say, it might be difficult to pin down the maker.
Regarding the frosting, I doubt they are frosted by acid but by mechanical abrasion. If interested, there is quite a long topic covering how items were frosted here:
https://www.glassmessages.com/index.php/topic,70868.msg397299.html#msg397299 . Reply 41 describes the abrasive frosting method.
As far as I’m aware, in the U.K. acid frosting (white acid) was developed by John Northwood c1867. The acid frosting is different from the acid etching used to make etched lines and patterns etc.
After acid frosting had been developed, items could still frosted by abrasion (and I think were quite likely to be if the object was a suitable shape).
Here is an abrasive frosted and acid etched goblet of mine that I’m sure is Richardson’s:
https://www.glassmessages.com/index.php/topic,70755.msg402733.html#msg402733