'Humdinger' began in MIDDLE ENGLISH - Middle English is the stage roughly during the four centuries between the late 1200s through the late 1400s.
From the Middle English -- ‘Dingen’ -- to beat or beater, for instance, "The new guy on that race horse is gonna digen everyone." or "That big boxer has never lost a fight, he's the grand dingen!"
'Dingen' came over on the Mayflower and 'Dingen' became 'Ding' - Because Americans and Australians are famous for slicing and dicing the English language and shortening words, in the early 1700s.
By the early 1800s we have evolved 'Ding' into the word "Dinger" in American English - the early American dialect the English were so fond of making fun of. Still meaning pretty much the same thing --- ' to beat, to surpass, to excel'.
By the mid-1800s 'Dinger' became more of a superlative noun -- "That horse is a Dinger!" meaning something outstanding of its kind.
After the American Civil War with such an incredible loss of life, the lines of the 'gentry' and the working man faded a great deal, former 'gentlemen' working right along side dirt farmers trying to scrape together a life from burnt fields.
Gentlemen attending to their higher educations in the past would, for instance, see a lovely woman, and would give a "hum" of acknowledgment -- like "Mmm, mm, mm" instead of voicing out loud, "Wow, what a dinger!"
Very much like we still do today, that ol' "Mmmm, mm, mm" is well recognized and well understood.
So, in more academic areas, trying to cover their rudeness, gentlemen would use the term "Hummer" instead of "Dinger"., as in "You boys should have seen the Hummer with the large...."
Now in a position to do so, the dirt farmer could simply ASK the former gentlemen, what is a Hummer?
Now we have "Hummer-Dinger" enter American English.
Well into the strict Victorian Age, the fast approach of Turn of the Century, the late 1800s, and a very quickly changing pace of life -- and once again we are back at slicing and dicing the English language and shortening words.
Enter ..... "Humdinger", 1900ish, Turn of the Century.
Rip snorter originally referred to something that was remarkable in some way. We like to think of this as being Australian, but in fact we swiped it from American English.
The rip part comes simply from the verb rip ‘to cut or tear apart’. And from the early 1800s it has been used as a general intensifier — you find it in riproarious ‘boisterous, violent’ and also the adjective ripper ‘excellent’ (e.g. a ripper guitar solo) — also exclamation ripper! (These particular uses are Australian).
The original snorter was, not surprisingly, someone or something that snorted (or snored), (1600s) and then in the 1800s it became a slang term for anything exceptional for size, strength, severity. It was often used in the context of weather, and it’s interesting that many of the early American uses of rip snorter are in reference to a severe storm or gale (e.g. it was a rip snorter of a nor-easter). American English extended it also to mean ‘a dashing, riotous fellow’. But it was really in Australian English that rip snorter took on the meaning of meaning something that is exceptionally good (early 1900s is the time when this sense appeared).
Bobby-dazzler means something striking or excellent. The earliest citation in the full Oxford English Dictionary for bobby-dazzler is 1866, and is interesting in itself. It says: what a Lancashire man would call a regular bobby-dazzler, a Cornishman would call a regular morgan rattler. (Morgan rattler is a strange one well have to leave for another day.) So, where does this expression bobby-dazzler come from, and how come dazzling is a property particularly belonging to Robert (rather than, say, John or Paul or George)? The verb to dazzle came into English in 15th century and seems to come from an Old Norse word meaning to confound or confuse. This rapidly came to mean to bewilder, confound or confuse the eyes or the vision. Anyone so attractive as to do so came to be called a dazzler a word that turns up around 1800. On the other hand, behind bobby (used as an adjective) is an 18th century word bobbish meaning in good health, in good spirits, in good humour. So anyone who is both sparkling with good health and good humour, and attractive to the eye, is a bobby-dazzler.