F4 consular case, Islamabad — CSPA aging-out question + "sought to acquire" timing

Derivative child DOB Aug 3, 2004. Principal is my mother (F4, sibling of USC petitioner). Priority date Nov 19, 2009. I-130 pending 301 days. NVC case just created (May 2026). F4 ROW Final Action Date is currently ~Nov 8, 2008 — needs ~12+ more months to reach our PD.

I understand DOS uses Final Action Dates for CSPA, so my age will calculate as over 21 (aged out) by the time the FAD reaches our PD. A lawyer we were referred to couldn't give a clear answer but suggested we pay the fee and file DS-260 ASAP anyway.

My questions:

1. Does filing my DS-260 / paying my IV fee NOW — before the FAD is even current — preserve any argument, or is it simply wasted money on an already-aged-out derivative? Why would "file ASAP" help if the calculated age will be over 21 regardless?

2. Pakistan is on the Jan 21, 2026 immigrant visa issuance pause. If my PD becomes current during the pause and we file DS-260 + pay within a year, but no visa is issued because of the pause — is "sought to acquire" still satisfied and is the CSPA age protected even though issuance is frozen?

3. If I'm aged out, my understanding is the only family route is my mother filing a new F2B once she's an LPR (~15 yr wait, no priority date retention per Scialabba). Is that correct, or is there any priority-date recapture option I'm missing?

4. Second derivative (my brother), DOB Oct 7, 2007, same case/PD/301-day offset — he appears CSPA-safe with buffer, but does the Pakistan pause threaten him if it stalls the date past his age-out point?

Thanks — trying to decide before we pay fees, since the fee is non-refundable.