"Are we crazy? Yes. You are crazy."
Translation:mamaw''a'? HISlaH. Sumaw'.
Both a longer stop and a short /u/ sound in between are possible; some Klingons even pronounce a double '' as a single ', though for the sake of clarity, it's probably best to avoid that.
In general, a syllable ending in an apostrophe can have a short sort of "echo vowel" after it -- je' might sound like je'e, for example. If the syllable ends in -w' or -y', the echo vowel will be a short u or I, respectively (matching the w or y rather than the vowel before that).
Personally, I use a longer stop -- similarly, qettaH for me has only one release but a longer stop, but some Klingon speakers (especially older ones) release the first t with a puff of air before articulating a second t.
Listen to https://hol.kag.org/sentence/maw%2527%2527a%2527. Then for comparison, listen to https://hol.kag.org/sentence/maw%2527a%2527 (with only one qaghwI'). This text reader is not always perfect (I left off the ma- prefix because it wasn't reading it correctly), but in this case it perfectly imitates the difference in how I hear Klingon speakers pronounce one qaghwI' versus two.
Watch carefully for when a sentence represents a question from one individual or group and then a reply from another individual or group. In this case "we" ask a question and whomever "we" are asking replies to us (replying to the "we" and not just to one person). Thus they are speaking to not just one "you", but to multiple "you", which means that they (and thus you, in your answer) have to use Su- and not bI-.
Though this winds up being a little tricky, our goal was to find a way to force the learners to sometimes use the plural you and not always default to the singular you. Please watch for these circumstances where we are trying to indicate that the "you" must be plural and use them as opportunities to practice using the plural-you prefixes and pronouns.
Let me answer your second question first. Yes, we have put this question and answer together in one exercise to force you to recognize this "you" as a plural "you", so that you have to practice the plural "you" and not just always answer with the singular "you".
But your suggested answer in your first question is incorrect. maw''a'? with no prefix (or as it is often called, the null prefix), can be "Is he crazy?", "Is she crazy?", "Is it crazy?", or "Are they crazy?", but it can never mean, "Are we crazy?" For that, the only option is mamaw''a'? (well, you could add the optional pronoun mamaw''a' maH?).
An argument could be made that we should accept mamaw''a'? HISlaH. bImaw'., but for the reason I stated in my first paragraph, we reject that answer.
Shouldn't «maw''a? HlSlaH. Sumaw'.» be right?
maw''a is missing the final ', but even if you added that, it would mean "Is he crazy?" or "Is she crazy?" or "Is it crazy?" or "Are they crazy?" -- but not "Are we crazy?". You need the prefix ma- (subject = "we", no object) for that: mamaw''a'?
And HISlaH has a capital i in the first syllable, not a small L.
Is this so you are forced to learn the prefixes?
Without context, "you" in English can refer to one listener or to many listeners.
So this sentence provides the context "we", to show that the second and third sentences use "you" to refer to several people, so that learners will practise the prefixes for "subject = you [several people]".