Yes, on both counts.

As written, one of them is more American in use, while the other is more British. Regardless, neither sentence is correct since handwriting is an uncountable noun and thus a (not an) handwriting is improper. The proper setence would he "He's got awful handwriting" using got because it is the participle used in phrases where "got" means "have" in all forms of English. However, "He has awful handwriting." is a perfectly fine sentence by itself, completing leaving out the word got.

From a grammar standpoint all three of your possibilities are fine. In this instance, they all mean more or less the same thing. There's no particular reason to prefer any of them. Although 'a third file' would have the most explicit meaning, as a native speaker, I would not be confused by any of the options.

"Set off from" means to leave the place that follows "from" "Set off for" means "to leave where one is right now for the purpose of travelling to the place following "for" So, for what you transcribed it means "people all about to leave musket practice."

I'll also add that 'until now' is usually used to mean that something was a certain way until this point in time, but now it is different. Example: I had never eaten mapo doufu until now. This means "Before this point in time, I did not eat mapo dofu, but now I am eating it."

"The baby sleeps with her mother" or "The baby shares a bed with her mother" are your best bet. Context and basic human decency will allow the listener to understand you mean those in a literal sense, and not the sexual slang meaning.

Both sentences are grammatically possible. The first sentence, however, implies that the question of guilt was recent or is ongoing. The second sentence would be better for talking about an incident that is no longer current.

3. Absolutely fell and washed. The present perfect tense just fails to make any sense with the sentence pattern. For 1 and 2, the choice depends. Different combinations are acceptable depending on what, exactly, it is you want to mean. Without more context you could for example say: He decided to do his homework before he watched the game --> a general statement of fact He had decided to do his homework before he watched the game --> emphasizing the deciding and a soft implication of a possible change He has decided to do his homework before he watches the game --> present tense. He is doing this now (or very recently) For number 2 the second half of the sentence is much the same. When did Jack do the divorcing? That will tell you what to use, although for the first part "told" is probably the best choice, even if "has told" isn't technically forbidden.