According to sources, Singapore Airlines will receive the first 787-10 in May 2018. The aircraft in question is ZC003 (LN 622) which is the fourth 787-10 that will be built in Charleston.
If the variable number block holds true then Singapore Airlines should also receive the 1st and 3rd 787-10 flight test aircraft, the first of which will start final assembly in December. The delivery dates of the first two flight test aircraft have changed as noted below:
ZC001 delivery date moved from 7/18/2018 to 10/10/2018
ZC036 delivery date moved from 8/1/2018 to 12/17/2018
ZC002 delivery date is still listed as August 2018
This means that Singapore Airlines should receive the first three 787-10 to be delivered in 2018 and Boeing should make 15-17 787-10 deliveries in 2018. I still don't know to whom ZC036 (LN 565) will be delivered.
787 Production and Disposition Table
787 Current Production Table