I booked my first xONEx this week. Thanks again all.

DONE3 with AA
The trip starts towards the end of January.
Everything after the dotted line is for travel after March 2025, so not on the fare calendar.
The dummy dates for the remaining 14 segments were booked into available dates/flight numbers over the subsequent 18 days remaining on the fare calendar.

I can't wrap my head around how and when I change the dates to something that is wanted and is available. Trip ends ~August 2025.

Today, the fare calendar is only open to 13 February.

If we want to travel BKK-HKG around 18 February, I'll be able to see that next week. But I can't change the subsequent 13 segments at that time because they're off the calendar.
Say I wait another month to change the date of BKK-HKG. Then the subsequent segments can be rebooked, but mostly with placeholders.

I could wait until September when the whole calendar is open for our travel days.

Is that when we change the dates?

What are the chances there is no availability for TWO seats in D for our city segments in February? (At the time of booking, one of the placeholder flights that I found did not have availability which trickled down after the agent found a new date.)

Or do we wait until after departure and change the dates for everything with only 4-6 week in advance of the next travel dates?

We're (almost) completely flexible but I am planning a lot of side trips that I'd prefer to book early.

Hope I'm making sense.
Advice/best practices?

CAI xAMM RJ
xAMM BKK RJ
.................
BKK HKG CX
HKG DPS CX
DPS KUL MH
KUL NRT JL
NRT HNL JL
HNL ANC AS
ANC LAX AS
LAX SJO AA
SJO DFW AA
DFW SFO AA
SFO MIA AA
MIA DOH QR
DOH AMM QR
AMM CAI RJ