Removing guests on resort reservation

[Disney Stine]

Hi all! I currently have a room only reservation booked for a solo trip. After some discussion, a family member may decide to join me but will not know until a few weeks before the trip. My fastpass day is arriving next week and I would like to add them as my second guest on my hotel reservation so I can book fastpasses for the two of us. We each have annual passes so my second guest will have tickets on my fastpass booking day.

Some questions I have ....
If my second guest decides to back out of the trip, can I easily remove them from my reservation with no fee and without losing my fastpasses and hotel reservation? I'm aware Disney has a new policy in place if a hotel reservation is cancelled then fastpasses booked are also cancelled. Wondering if this extends to modifying guests.
Lastly, if I decide to add the dining plan after they are removed, Disney will only charge me the dining plan for one guest (me) correct?

Thank you for all of your help. :]

 

[DisneyJoe]

Regarding a penalty fee:
Since it is a room only reservation, the rules are as follows:

- You can change or cancel your reservation without penalty up until 5 days prior to check-in. (6 days for online bookings.)
- The cancellation penalty for cancelling less than 5 days from check-in is the first night’s room rate (which was the deposit). A no-show is considered a cancellation and has the same penalty.

You will not lose your FP+ if removing the second guest, only if cancelling the entire room reservation.

Disney will only charge you for the dining plan for the number of guests currently on the reservation.