1) "чё" is the same as "что", only colloquial and less polite.

2) "Who, me? But of course!" - Here "дык" is more or less a substitute for "так" or "так ведь": an interjection implying some sort of explanation afterwards (however, here he just says "of course"). "-то" is a particle which terms of use are difficult to describe.
Let's just say that in one highly theoretical article on the subject it was desribed as a contrast marker operating as follows. There are some objects A,B,C... And some properties X,Y,Z.. Not mutually exclusive, I mean. -ТО in declarative sentences is used in constructions like "A-то has property X". It marks the information known by the hearer and makes him activate alternatives in his/her mind: if A has X, then what property X,Y,Z.. does B possess? What property does C has? For example "Me, I've brought vernier caliper". Now, you have a peson with a caliper and a set of other people that brought a caliper, a pen, or maybe something else.
Information on A marked by -ТО is assumed to be known by both the speaker and the hearer (though not yet activated in hearer's mind).
In questions+answers like in your example ("Are you human?", "Did Jack bring some milk?") it is quite simple: the one who answers "Я-то?", "Джек-то?", "Книга-то?" simply emphasizes once again that they are talking about the same object/person: "Me (precisely me among other people)? Of course!"
I suggest that you just keep track of typical uses of that particle rather than dig into that theoretical explanation. After you collect some examples, it is going to be easier to see the patterns.

3) "Меня звать" is an older variant (you may easily see it in 19th centure books) and probably not as literate. Cannot comment on this, by subjectively I feel it shows that a guard is a simple fellow.

4) It's hard to tell. "о" in "это" is unstressed, so in speech it may be hard to hear if it's there or if it disappears between "т" and the first consonant of the next word. Consider this one more way to show that the guard isn't exactly a bright guy.

5) A colloquial meaning of "сечь" ("to whip" or "to slash to pieces") is "to understand", "to get the idea". A perfective for this meaning is "просечь" - "to get it".