Solutions for Act III Scene 2 - Double Duty

The pairs of words here are obviously alliterative, so the first letter in each line is likely important. The title "Double Duty" implies the words are providing more information than just initial letters though, so we can expect the rest of each word is also important.

The trick is to notice that each phrase seems to be an unusual transformation of a far more common alliterative pair starting with the same letter. Specifically, the transformation is to take this common phrase, convert each word to a synonym, and then convert the first letters of these synonyms back to the original phrase's initials. For example, we can see "soil sating" can be converted to "foil eating", which is itself synonymous with "sword-swallowing", a much more common phrase that also starts with S.

Since it can sometimes be difficult to hit upon the right words when replacing the initial letters of the lines given, an easier approach to solving this puzzle can be to work from both ends simultaneously - that is, think up common phrases starting with the given letter and check if it has synonyms extractable from the given line. Altogether we get the pairs:

LineSynonymsCommon phrase
soil satingfoil eatingsword-swallowing
drank dabfrank tabdirect debit
sail salehail galesnow storm
sounding socksbounding rocksskipping stones
cation cubnation hubcommunity centre
few ferriesnew berriesfresh fruit
ATAR-divining aidestar-divining sideastrological aspect
airy aightwiry mightathletic ability
horrid hoptorrid tophot-head
suffer sawsbuffer lawssafety standards
sane sine-detectorlane mine-detectorstreet sweeper
gravel garnertravel earnergo-getter
barge bodslarge podsbroad beans
uncrease ureincrease ereup until
pad pooleddad fooledpop psych
siled sipperfiled dipperslotted spoon
bear bubsrear pubsbehind bars
argent actusurgent ictusacute accent
mump mewslump newsmass media
undisputably unactiveindisputably inactiveutterly useless

Now we just need to extract a final answer. We obviously can't read off the first letters, since they were given to us from the start. Looking at last letters could also be an option, but many could be guessed from the original words (depending on certain inflection suffixes). So the next most natural letters to look at should be the second ones. These are bolded in the above, and can be seen to spell out two messages depending on if you're reading from the first words in each phrase or last words in each phrase. These messages respectively are WINK OR STOAT OR POLECAT and WETTERS BETWEEN SPACES.

These seem to be following the same mechanic, so translating the messages to Mink or stoat or polecat and Letters between spaces, we arrive at the alliterative phrase weasel words, which very loosely describes what we've been dealing with here (obfuscated synonyms).

Design notes:
We went through many versions of this puzzle before being satisfied that there were enough fair clues. It was quite hard to find common alliterative phrases for certain lines, so apologies if a phrase was considered less than common. This was obviously dictated by the two messages extracted at the end, and many possible pairs were tested with even less favourable results... Interestingly, the final line requiring a message like "_T... _S..." proved especially annoying, but we couldn't find a neat replacement because it seems every other member of the weasel family ends in T (the stoat, polecat, and ferret).

The answer is: weaselwords