Yes, I recommend using the same account.
Your phones will automatically get their own folder per user in Mylio, so that should be easy to distinguish photos from different phones.
If you want to be able to see e.g. a separate Calendar view for each user, the easiest is to add a “Category” for each family member (e.g. “John”, “Jill” and “Jane”) and then mark each of those Phone Camera Roll folders with the category for the family member.
If you have additional photos from other sources as well, that you also want to keep separate, just place them in per-user folders as is most practical to you, and then also mark those folders with the appropriate categories. For pictures that are common between everybody, just tag a folder with all 3 categories.
This way you can enable a top-level filter in Mylio and you can at any time select whether you just want to see your pictures, or your wife’s or daughters, or a combination of multiple users.