Your Q about US Bombs has been missed by others. It is core to a/c types and numbers.
When Healey committed 17/5/65 to 200 Jags and 175 AFVG he was also dealing with silly-sized RAF bids for F-4s, to settle later as 118. What has not been explored by others is...What AW would Labour buy? The Election Manifesto had defused their CND wing with the formula "(We) are not prepared (to waste) resources on endless duplication of (US) strategic (AW: misheard as: no new UK AW)”. Their first decision was to proceed with 4xSSBNs to patrol from 1969: he was told that meant (4x16x3) 192 warheads plus the maintenance pool. From 2/53, when PM WSC put fission Blue Danube into production, to (30/4/65) MoS had supplied 320 AW to RAF/RN, who on that day had on hand 146, plus 64 US Bombs in RAFG (BAOR had access to 104 US warheads). No way, Jose, could AWRE/ROF do SSBNs, replace US Bombs in RAFG, while meeting a shopping list in 00s for light WE177A on RN Buccs, FEAF F-111K, as NDB, and much more. No new AW?
So: obvious next decision, rollover RAFG's US Bombs onto F-4M. (So, 60xB57 opnl. 1/7/70, days after he left Office). Gain UK sovereignty in RAFG with AFVG/WE177B. On 29/6/67 nice Marcel D deleted AFVG; on 16/1/68 Cabinet deleted EoS, so F-111K.
UK AW production workload could now equip RAFG c. '72: so: new+ex-EoS RN Buccs; redefine (most) UK Jags as S: all with WE177B (became C, opnl Bucc 31/12/72, Jag 1/12/75) which could (honestly) be presented as not new. F-4Ms to replace Lightnings and iron Attack.
None of this was a Grand Plan. Much fissile material for WE177s came from salvage and from an SSBN loadout, when someone noticed we could not crew 4 SSBNs. so: no new AW.
So: my A to your Qs: AFVG was to replace AW F-4Ms and NEAF/FEAF reroled Vulcans; no effort to hang US Bombs on Jag. (Italy would do Atlantic NDB, Italy and FRG B61/Tornado, so painful that FRG has just selected F-35A for its AW Task, and not to attempt B61/Typhoon).