I'm sorry for not making it clear earlier. There are only two children who are my spouse's biological kids, and they are both PR now. I am also in the process of becoming their legal parent in Taiwan. Therefore, I would like to know if, by using Taiwan's legal adoption documents, they can obtain citizenship together with me?
You brought this up in a separate thread.
I suggest you contact a lawyer if you're not satisfied with the answers here.
Note that while it varies by province, adopting one's spouses children (your stepchildren) is generally MUCH easier and can be done directly by application to the court. You can find it out about Ontario, for example, here:
https://www.ontario.ca/page/adopt-stepchild-or-relative
Obviously there are matters of import here such as whether the other biological parent has given up rights and/or approves.
It is my belief/understanding that IRCC's approach to recognizing adoptions elsewhere (eg Taiwan) is SUBSTANTIALLY different than for other types of international adoption for cases where it's a stepparent adopting and the other parent is the current legal spouse. In other words, roughly akin to the Ontario situation above.
I believe that will be sufficient to get your adoption 'recognized' in Canada. Not sure how you go about this though because the kids are already PRs. Conceivably you could adopt them in Canada (where they now, after all, reside).
It may be that the only way to determine for sure is to apply for citizenship for the kids on the basis of the adoption orders and ... see what happens.
But again, I think the point to emphasize in all cases is that this is NOT the usual type of international adoption. One biological and custodial parent is married to a new partner (stepparent), who has adopted (with permission/abandonment of rights) of the other biological parent. Stepparents adopting their stepchildren is a privileged case in many jurisdictions.
I don't have direct experience with this. I do know of cases where one stepparent adopted with no issues vis a vis IRCC/Canadian authorities, although cases where one biological parent was deceased and the other remarried. That's an important difference but not necessarily a critical one.