May you live long. means I wish you live long. Might you live long. means I allow you, or maybe you live long. :)

A few suggestions here: 1.Learn correct pronunciations of consonants and vowels. Many people don't manage it because of their dialects. 2.Take time to go through rules of liaison(eg. I-am, for-us), incomplete plosion, and intonation patterns, etc. 3.Find proper listening materials with subtitles then listen to and mimic it repeatedly until you feel natural about it. 4.Try to talk to native speakers and get advice from them. This could be very effective. For rules and regulations, we want them for a better pronunciation, and we have to practice with correct knowledge of them to get solid skills. Wish you good luck!

(a) is not correct, because "he and his brother" contains two persons, so you must need a plural form of "be", which means you should use "are" instead of "is". So, the correct form of (a) is "He and his brother are coming." (b) is correct, because "as well as" is a phrase used as a preposition, so the subject of this sentence is "he", so we use a singular form of "be", which is "is". As for (a), the "and" between "he" and "his brother" is a connective. This is the difference between these two sentences.

A better way would be: If he is happy without me, then I will be super happy.

B. is correct. Because "as well as" is a preposition phrase, so the subject of this sentence is singular. A. is the plural form in present continuous tense. C. is the plural form in simple present tense. D. is the plural form in past continuous tense. Only B. is the singular from, which is in simple present tense. So you would choose B.