Well, since these are all colloquial forms, you could make an argument if any of these are “grammatically” correct at all (and you probably wouldn’t use any of these in formal writing), but it is how Welsh is spoken, and as such these are all correct Welsh.
That being said, keeping in line with the colloquial nature of these forms, I’d place the pronoun after the verb:
Sa i wedi gweld chi am sbel. (and so on)
Usually any Welsh is better than no Welsh, but please keep in mind that this forum is for learners and speakers of all levels. These questions are best asked in English only (or Welsh with an English translation), so that as many learners as possible may benefit, regardless of their level of understanding Welsh.
There is a forum topic, where you can try out your Welsh to your heart’s content, check it out here, if you haven’t seen it before:
https://en.forum.saysomethingin.com/t/be-dach-chin-gwneud-a-topic-to-practise-writing-welsh-open-to-all/
Pob lwc, a dal ati!
