Readers query usage and spelling

L. Singh, who has written to Twisty Tongue in the past, enjoys crossword puzzles. He wrote, “Clues such as ‘change for the better’ sometimes want amend and sometimes want emend. What’s going on?”
Amend actually means, “To put right; change for the better.” Emend, when properly used, means, “To change a literary work; to edit.”
If the puzzle clue states, “Change for the better,” the correct answer should be amend. But those who create crossword puzzles are seldom careful about such fine differences.
No help is found in the Thesaurus. It offers many of the same synonyms under each of these two words. In fact, Singh will probably find emend and amend listed there as synonyms for each other if he checks. 
This is because the Thesaurus collects words with both similar and precise meanings. It follows that many listings bear only a vague relationship to the original word. Also, it seems that puzzle makers sometimes deliberately select a synonym only remotely related to the clue.
An anonymous reader asks about doubling letters. He/she writes, “I spell traveller with two ls and I have always written kidnapped not kidnaped but I see these words spelled traveler and kidnaped all the time.”
Questions of English, a handy little book put out by Oxford, deals with this very topic.
This source says American spelling quite often does away with unneeded letters and adds, “American spelling is often more straightforward and regular than British, partly as a result of reforms suggested by the great lexicographer, Noah Webster.”
Questions provides examples — anesthetic/anaesthetic; favor/favour; program/programme; ax/axe.
Re the problem posed by “anonymous,” According to Questions, “Some verbs which in British English double the final consonant when a suffix is added, often do not do so in American English, e.g., traveled, traveler, kidnaped, worshiped, combated.”
CP Stylebook also offers advice: “We double the l at the ends of words when adding a suffix: travelled, 
rivalled, medallist.
We’re probably okay in using one l unless we’re writing for print, in which case editors will ensure our work conforms to the publication’s style.
I usually go with a single l but would write kidnapped, worshipped and combatted (although I’ve never used the word combatted).
I think I double some consonants because I unconsciously consider pronunciation. Traveler, spelled with one l or two, will never be mispronounced. We cannot say the same about kidnapped written kidnaped.
Questions mentions a few simplifications suggested by Webster which never caught on even with Americans — bred (bread), helth, beleeve, yeer, rong, ritten, munth, laf, examin, obleek, and mashine.
L.V.G. asked, “Is there a word for a sentence that uses all the letters of the alphabet? When I took typing years ago, we practiced, ‘The quick brown fox jumps over the lazy dog,’ because it uses every letter, but I don’t think any name was mentioned for that kind of sentence.”
Such a sentence is called a “pangram.”
There’s no word for a sentence which uses each letter of the alphabet only once.