Non-definig relative clauses

[Elvis]

Am more confused now ,,guide me please:these sentences
1-Your letter was interesting.I got it yesterday.
2-My parents have always lived in the centre of the town.Your father met them last year in Paris.
3Every morning my father drives me to school.He works for a computer firm.

I have some ansewrs for making a non definig relative clause but I have a feeling that the answers are too weak and not right in a sense..

1-Your letter was interesting,which I got yesterday.
2-My parents have always lived in the centre of the town,whom your mother met last year in Paris.
3-Every morning my father drives me to school,who works for a computer firm.
I do know that they should be done this way

Your letter ,which I got yesterday,was interesting.
My parents.who(m) your mother met last year in Paris,have always lived in the centre of the town.
but is the first answers I wrote still acceptable or wrong grammatically.
Thanks in advance for those who answer .......and have a nice weekend.

[Lorikeet]

You need to have the clause come after the word it is modifying. All your other examples are wrong.

Your letter, which I got yesterday, was interesting. Is correct. "Which I got yesterday" is about the letter.

Your letter was interesting which I got yesterday is not correct. "Which I got yesterday" does not talk about "interesting"