I appreciate the wealth of info on this board already. I've been scouring through decades worth of detailed and valuable information here and am hoping to get clarity on some nuances specific to our current and future situation. Hoping some folks are still watching this.

Background
-Me: US citizen, SG EP holder, no SG PR.
-Wife: Singaporean citizen, US PR. Left Sg for uni and has not worked here.
-Incoming: Son, who will be born in Singapore (SC by birth). We will also immediately register for US citizenship by descent.
-Other children: 2 daughters with USC (birth) and SC (descent). Both pre-K or younger currently.
-Property in Singapore: None
-Time in Singapore: 3yr assignment total, ending 2026. Short visits to see family thereafter.
We plan to return to the US when my assignment in Sg is completed. We have no intention of living long-term in Singapore as a family unit once we return to the US. I understand that we should:
-Not apply for Sg passport at all. Same for IC.
-Not claim Baby Bonus, gov't paid leave, etc.
-Keep a clean slate as early as possible, and certainly after age 11.
-Announce intentions for our son to renounce to CMPB, MinDef, and ICA early and often. Specifically at these three points: when we leave the country, at age 11, and at age 13.
Question: If my wife does not renounce her SC, to what extent is that known to jeopardize any request to defer our son's NS until 21 for him to renounce? We are reluctant for her to renounce her citizenship in case she needs to return to care for her parents in the future. We will have otherwise completely divested from Singapore's public benefits financially and hold no property here.
If she did need to move, we anticipate it would either:
(1) be after our children are adults, or
(2) uproot our entire family, at which point we would willfully expect our son to serve NS.
We are ultimately trying to determine if we should consider NS as guaranteed if my wife does not renounce. Doing so would prevent us from needing to walk on eggshells for the next 18+ years and would open us up to additional possibilities to prepare for that future.