Syntax: This is a present perfect construction ('It's been so long') followed by a relative clause ('that I haven't seen your face'). The repetition of 'long' is an example of reduplication for emphasis, common in informal speech and music.
Morphology: 'Been' is the past participle of 'be'. 'Haven't' is the contracted negative form of the present perfect auxiliary 'have'. 'Seen' is the past participle of 'see'.

Syntax: The structure 'I'm trying to be strong' uses the present continuous tense to indicate an ongoing effort. The second clause, introduced by 'but', presents a contrast. 'Washing away' is a phrasal verb used metaphorically.
Morphology: 'Trying' is the present participle/gerund of 'try'. 'Washing' is the present participle of 'wash', functioning as part of the passive progressive construction 'is washing away'.

Syntax: This segment uses simple past tense ('were made', 'showed', 'said') to describe completed past actions. The phrase 'between us two' is a slightly formal or emphatic way of saying 'between the two of us'.
Morphology: 'Mistakes' is a plural noun. 'Were' is the past tense plural form of 'be'. 'Showed' is the past tense of 'show'. 'Weren't' is the contracted negative past tense of 'be'.

Syntax: This is a complex sentence. The first part is a question starting with 'Why'. The second part, introduced by ''cause' (a contraction of 'because'), provides the reason for his longing. The list 'homie, lover and friend' uses polysyndeton (multiple conjunctions) for emphasis.
Morphology: 'Was' is the past tense singular form of 'be'. 'Are' is the present tense plural form of 'be'. The nouns 'homie', 'lover', 'friend' are in a coordinated series.

Syntax: This segment mixes simple present ('I miss'), present continuous ('watching'), and future construction with 'gonna' (going to). The phrase 'apple of my eye' is a fixed idiom. 'Till' is an informal contraction of 'until'.
Morphology: 'Can't' is a contraction of 'cannot'. 'Miss' is a base form verb. 'Watching' is the present participle of 'watch'. 'Goes' is the third-person singular present tense of 'go'. 'Get' is a base form verb. 'Gonna' is a phonetic representation of 'going to'.