Yes, so you can click to the report a problem to announce to the contributors ;)
I tend to say no. without "không" at the end of the question, it sounds more like an exclamation rather than a plain yes/no question. "what? you have a snake?!" vs "do you have a snake?"
The pronunciation of the noun 'rắn' sounds like 'sắn'. Is tit suppose do be that way? Dialects from North and South Vietnam?
How are you supposed to know this is a question and not a statement when the last word has a rising tone either way?
Normally, you can tell by the intonation and the scenario of the text. However it might be slightly difficult to tell in this case as there's only one sentence. Both answers in statement or question form are accepted in this example.
The below sentences can be understood as questions. In this course we will be focusing on using 2-3 methods of phrasing a question to simplify the grammar.
Bạn có một con rắn? (Short form, with intonation or in specific scenario)
Bạn có một con rắn phải không? (You have a snake, right?)
Bạn có một con rắn đúng không? (You have a snake, right?)
Bạn có một con rắn à? (You have a snake, yea?)
Bạn có một con rắn hả? (You have a snake, huh?)
I don't totally agree with you. when there's no không or other question markers like those you mentioned, it is still a question but the speaker would sound more like someone in disbelief: "what, you have a snake!?"