A more-likely probability about Great-great grandmother Célina Boulé (1840-1928): was she adopted?

In a previous posting, I laid out the mysterious case of my great-great grandmother, Célina Boulé.

I mentioned this on the Ancestry.com discussion boards and got some very interesting help and commentary from several users.

At the time of the previous posting, I was convinced that the problem was just an imperfect set of data: basically, she wasn't recorded with enough definition to make as "easy" of an identification as most of the other people in the tree.

Thanks to daciodan (who also turned me on to the LaFrance site), it appears that her parents are NOT Moïse Boulé and Basilice Bernier - at least they're not her "official" (birth/legitimate) parents but there DOES appear to be some (un-ascertainable) connection.   That leaves (broadly) two options:

1. she was illegitimate;
2. she was adopted.

The available records don't provide any insight into this, of course (I have seen baptism entries in Drouin that do make it clear the child  is illegitimate, but I don't have one for Célina), and adoption might not have "officially" taken place.

Another mystery is that she sometimes appears under the surname "LaLiberté" which isn't a 'dit' name for Boulé, but a search of the "Lotbinière metro area" under LaLiberté doesn't provide any concrete leads, ALTHOUGH - once again - there appears to be some potential connection to a LaLiberté family who at least at one time lived near the Boulé family.   Perhaps the illicit relation was between a Boulé and a LaLiberté?

Update - Dec. 2018:

At this point the most plausible theory is that she was adopted.    But what of her origin? 

1. She was illegitimate and neither of her parents are known.
2. She was a (legitimate) orphan but (for whatever reason) her origin is unknown.
   

I've come to the hypothesis that she COULD actually be an Irish orphan fleeing the potato famine.  While that doesn't explain the absence of parents in the marriage record (that implies that she is in fact an "enfant naturel" with unknown parents, my DNA background is completely mapped to the 5th generation EXCEPT for Célina's parents, and the ratio of Irish/French background fits better if she is Irish and not French.   That's not conclusive in of itself, but it does set up an interesting experiment, if I can identify enough DNA 4th cousins whose family trees overlap to each other but NOT with mine.