Traveling MCO to CDG via JFK on Thursday. Tickets were booked through Delta and flights to/from CDG are Delta codeshares with AF (booked under Delta flight #)

Traveling under 2 separate PNR's (mine for 3 persons, MIL for 1 person)

All have assigned seats for MCO - JFK.

Only 3 have assigned seats for JFK - CDG (I believe due to equipment change). This is Delta #8581 or AF #007.

As of now MIL does not have an assigned seat (reservation is confirmed) and is concerned about being bumped.

Have called Delta and Air France but no one has been able to get her a seat assigned (have been told that it will be assigned at airport).

In addition, no luck with Delta or AF websites.

As her ticket is confirmed, what is the liklihood of MIL being bumped to another flight (she does not want to cross Atlantic by herself)?

When they say "at airport" for seat assignment, is that at MCO or JFK?

How many seats are normally held back for gate assignment?

If she does get bumped, will they allow her to take my seat and let me take the bumped flight (at least she would then travel with my wife and daughter)?

Any responses appreciated, as MIL is really concerned that she will be bumped.