"I like you."
Translation:Dw i'n licio chdi.
Somewhere I'd got the idea that in sentences such as this, where the object of like is a pronoun, that a different construction is used, e.g. Dw i'n eich hoffi chi. This seems to be confirmed by the final section of https://www.bbc.co.uk/wales/learnwelsh/pdf/welshgrammar_f_pronoun.pdf. Please could somebody explain what the correct situation is.
The pattern that you mention is correct and is widely used. However, it is often not introduced early on in basic courses such as this one, where the more informal pattern is introduced first.