I am trying to book a flight on DL.com for I Class Business Fare that's codeshared on a China Airlines metal flight, on the booking page it says:

The ticket is non-refundable.

After clicking in to read the fare rules, it says:

CANCELLATIONS

ANY TIME
CHARGE TWD 3500.
CHILD/INFANT DISCOUNTS APPLY.
WAIVED FOR ILLNESS OR DEATH OF PASSENGER OR FAMILY
MEMBER.
NOTE -
1. FARES ON A TICKET FROM DIFFERENT RULES WITH THE
SAME OR DIFFERENT CANCELLATION FEES
-APPLY THE HIGHEST FEE OF THE CANCELLED
ITINERARY THEN REFUND ANY REFUNDABLE FARES
AND THE NON-REFUNDABLE FARE AMOUNT WILL BE
RETURNED TO A NON-REFUNDABLE VOUCHER FOR
TRAVEL GOVERNED BY DL ONLY
2. ILLNESS/DEATH WAIVER MUST BE SUBSTANTIATED BY
A VALID MEDICAL/DEATH CERTIFICATE
3. CANCELLATION FEE DOES NOT APPLY TO INFANTS
UNDER 2 NOT OCCUPYING A SEAT
PER TICKET CHARGE FOR LOST TICKET APPLICATION IS
USD 100.00/CAD 146.00

Does that mean if the ticket were to be refunded, it will only be refunded into credit (minus the TWD 3,500 penalty) on DL future purchases?

CHANGES

ANY TIME
CHARGE TWD 2000.
CHILD/INFANT DISCOUNTS APPLY.
NOTE -
-ALL TICKETS MUST BE REISSUED
-PENALTY DOES NOT APPLY TO INFANTS UNDER 2 NOT
OCCUPYING A SEAT
-SEE /CHILD DISCOUNT/ IN FARE RULE TO DETERMINE
IF CHILD DISCOUNTS APPLY
-CHANGES RESULTING IN A HIGHER FARE MUST BE ADD
COLLECTED AT THE TIME OF REISSUE
-IF THE CHANGE RESULTS IN A LOWER FARE THE
DIFFERENCE LESS THE PENALTY FEE MAY BE REFUNDED
TO THE ORIGINAL FORM OF PAYMENT
-MUST COMPLETE TRAVEL BY 1 YEAR FROM THE DATE OF
COMMENCEMENT OF TRAVEL
-FARES IN DIFFERENT RULES WITH THE SAME OR
DIFFERENT CHANGE FEES - APPLY THE HIGHEST FEE OF
ANY CHANGED FARE COMPONENT ON THE TICKET
-THE CHANGE FEE OR ITS EQUIVALENT WILL BE
CONVERTED AT THE BANK RATE AT TIME OF REISSUE

If I were to make changes, does that mean I would have to pay TWD 2,000 if I class is available and + fare difference if I class is not available?

Also, since this is a codeshared flight where seat selection is not available. If I were to call DL, would I be charged for a reservation fee? If not, should I just request a CI PNR from DL instead of asking them to select seats for me and try to select seats on CI's website?

Thanks for any help!