Compare the following sentences:

1. 妈妈昨天喝茶，今天喝咖啡。
2. 妈妈不喝茶，她喝咖啡。

Sentence (1) seems quite straightforward: the pronoun is omitted because it is clear who is being talked about and there is no need to specify. If we were to use the pronoun, ie,

妈妈昨天喝茶，她今天喝咖啡。

would the meaning change at all? My sense is that by using the pronoun we add an element of vague causality, almost conditionality: "if mom drank tea yesterday, she'll probably drink coffee today."

As for sentence (2), the opposite feels true to me: without the pronoun it feels like a list of two true facts, perhaps related but with no comment as to the nature of their relationship:

妈妈不喝茶，她喝咖啡。

If I take out the pronoun though, it all of a sudden feels as though it were an abbreviated form of a conditional sentence:

妈妈不喝茶，喝咖啡。

feels to me like

妈妈不喝茶（的话，就）喝咖啡。

Question 1, what do you think of my above analysis?

Question 2, if my above analysis is accurate, it is actually a quite interesting situation: in sentence (1) we achieve a neutral listing of facts by omitting the pronoun, while in sentence (2), we achieve a similarly neutral listing of facts by including the pronoun. What's more, it seems that the inverse sentences would produce a similar effect: pronoun inclusion in (1) and pronoun omission in (2) both appear to imply a vaguely conditional relationship between the two clauses. How do we explain this situation?

Compare the following sentences:

1. 妈妈昨天喝茶，今天喝咖啡。
2. 妈妈不喝茶，她喝咖啡。

Sentence (1) seems quite straightforward: the pronoun is omitted because it is clear who is being talked about and there is no need to specify. If we were to use the pronoun, ie,

妈妈昨天喝茶，她今天喝咖啡。

my sense is that we would either be making a very clunky sentence or we would be adding an element of vague causality, almost conditionality: "if mom drank tea yesterday, she'll probably drink coffee today", almost as if we were saying an abbreviated form of:

妈妈昨天喝茶（的话），她今天（就）喝咖啡。

As for sentence (2), the opposite feels true to me: without the pronoun it feels like a list of two true facts, perhaps related but with no comment as to the nature of their relationship:

妈妈不喝茶，她喝咖啡。

If I take out the pronoun though, it all of a sudden feels as though it were an abbreviated form of a conditional sentence:

妈妈不喝茶，喝咖啡。

feels to me like

妈妈不喝茶（的话，就）喝咖啡。

Question 1, what do you think of my above analysis?

Question 2, if my above analysis is accurate, it is actually a quite interesting situation: in sentence (1) we achieve a neutral listing of facts by omitting the pronoun, while in sentence (2), we achieve a similarly neutral listing of facts by including the pronoun. What's more, it seems that the inverse sentences would produce a similar effect: pronoun inclusion in (1) and pronoun omission in (2) both appear to imply a vaguely conditional relationship between the two clauses. How do we explain this situation?