4.) The A.B.C. Murders sound interesting. Is it available on Switch?
I don't believe so, no. Honestly, A.B.C. Murders is the one I recommend the least of all of them. I'd say read the book instead.
The game epitomizes the traditional "3D detective adventure game", and I included it as my least least-favorite example of that sort of detective game. Mostly because a lot of the issues I have with games like the Frogware Sherlock Holmes games are fixed in this game due to the story having already been written, but the writer still tries to fill some gaps with gameplay and deduction and it's still weak in that department.
I want to go ahead and throw my two-cents in, but if your heart is set on a detective game that presents fully-clued, fair mysteries that you can puzzle out, I'd recommend straying far away from the Sherlock Holmes games. The games somehow manage to be both of boringly hand-holdy, as well as unintuitive, and oftentimes you'll be punished if you actually figure stuff out before the game expects you to because the game doesn't let you "reason stuff out" in its deduction system until it wants you to. And oftentimes, if you CAN use the deduction system, it becomes a guessing game of what the game wants you to say because there's often a million different viable connections between clues but it only takes one (another symptom of the game getting mad at you for being ahead of it).
The games issues mostly come from what I think is a strong familiarity with Sherlock Holmes but an otherwise lacking experience with the genre they're trying to emulate. Sherlock Holmes is canonically not meant for the reader to solve -- Watson himself admits to hiding evidence from the reader to make Holmes look even smarter, because he sees his job as being something like a hypeman to Holmes. This comes from the fact that often times Holmes's deductions aren't 100% possible to follow until he explains them, and sometimes not even then (because we don't have all the information anyway). A good example is the story "The Red-Headed League", where Holmes mentions that a man's knees were dirty -- this being information we're not privy to until the denouement. And, oftentimes, Holmes's observations are accompanied by a strong library specialized information -- information he either already knows, or has documented.
The ability for the reader to solve the crime didn't come about until about 1917, around when the "Golden Age" of mystery fiction began. From 1917 to sometime near the 1970's, mystery novels focused entirely on being fairplay and fully-clued, allowing for the reader to deduce the same things the detective does -- being able to solve the crime, not only naming the culprit but also explaining the complex methods they employed to commit the crime.
The problem is that Sherlock Holmes-styled clues aren't very conducive to a fairplay, the-reader-solve-it mystery, and the games are shockingly faithful to Holmes. The game asks you to solve the mystery as you play, but problems come in two forms:
1.) The most important clues being too obvious, so you're way ahead of the game in terms of where the mystery is going, but the game won't let you get there until the little shit is pieced together.
2.) The little shit's clues are often times unintuitive and it's hard to find out which of many combinations of likely deductions the game wants you to do.
There also seems to be a lack of working knowledge of a lot of the conventions of cluing and mystery fiction present in these games. Red herrings are often the most basic and transparent they could manage, and a lot of the clues don't have many fun alternative interpretations besides the most obvious one.
Basically, I can't recommend them to you as a good introduction to detective games unless you're a die-hard fan of Holmes who needs to consume all Holmes media, and even then I'm not 100% sure the games will be a satisfying exercise in solving for you.
The ABC Murders game addresses these issues slightly because, being a Golden Age mystery, the original novel makes its deductions apparent and intuitive. But it still suffers from a lot of the genre-unaware issues that I feel plague the Holmes and Frogware Holmes games.