It's a bit late, but here's a similarly updated list for the LNWR fleet/stations (as of 4/12/19).
Stations
WCML
All WMT-managed stations on the WCML have two-tone green/white LNWR lampposts from Watford Jct to Acton Bridge (inclusive).
>Acton Bridge: LNWR running boards/signage.
>Hartford: LNWR running boards/signage.
>Winsford: LNWR running boards/signage.
>Rugeley Trent Valley: LNWR running boards/signage.
>Lichfield Trent Valley (Low Level): LNWR running boards/signage.
>Tamworth: LNWR running boards/signage (both levels).
>Polesworth: LNWR running boards/signage.
>Atherstone: LNWR running boards/signage.
>Nuneaton: LNWR running boards/signage.
>Long Buckby: LNWR running boards (inc. "Direct Trains to Birmingham International" transfers), LM signage (AFAIK).
(Updated as of 29/01/20)
>Northampton: LNWR running boards/signage (inc. "Direct Trains to Birmingham International" transfers).
>Wolverton: LNWR running boards/signage (inc. "Direct Trains to Birmingham International" transfers).
>Milton Keynes Central: LM running boards/signage.
>Bletchley: LNWR running boards/signage (inc. "Direct Trains to Birmingham International" transfers).
>Leighton Buzzard: LM "Olympic gold" running boards,
LNWR signage.
>Cheddington: LNWR running boards/signage.
>Tring: LNWR running boards/signage. (N.B. One lamppost behind P1 is still in LM green/black).
>Berkhamsted: LNWR running boards/signage (inc. "Direct Trains to Birmingham International" transfers).
>Hemel Hempstead: LNWR running boards/signage (inc. "Direct Trains to Birmingham International" transfers).
>Apsley: LNWR running boards/signage.
>Kings Langley: LNWR running boards/signage.
>Watford Junction: LNWR running boards (inc. "Direct Trains to Birmingham International" transfers; except large illuminated ones - those are still LM), LNWR signage.
Abbey Line - all have LNWR running boards, signage & two-tone green lampposts.
Marston Vale Line - all have LNWR "Marston Vale" running boards & signage.
>Fenny Stratford: LNWR two-tone green lampposts.
>Bow Brickhill (for Caldecotte and Tilbrook): Partial
LNWR "Marston Vale" signs/signage, green/black (LM) lampposts (AFAIK).
>Woburn Sands: LNWR two-tone green lampposts.
>Aspley Guise: Green/black (LM) lampposts (AFAIK).
>Ridgmont: LNWR two-tone green lampposts.
>Lidlington: LNWR two-tone green lampposts.
>Millbrook (Beds): LNWR two-tone green lampposts.
>Stewartby (for Kimberley College): LNWR two-tone green lampposts.
>Kempston Hardwick: LNWR two-tone green lampposts.
>Bedford St. Johns: LNWR two-tone green lampposts.
Trains
Class 230 - all refurbished and in full (Marston Vale) LNWR livery
Class 319 (due to leave the franchise upon introduction of Class 730s)
319005: Thameslink livery, unbranded
319012: Thameslink livery, unbranded
319013: LM livery, LNWR branding
319214: Thameslink livery, unbranded
319215: Thameslink livery, unbranded
319216: LM livery, LNWR branding
319217: Thameslink livery, unbranded
319218: Thameslink livery, unbranded
319219: Thameslink livery, unbranded
319220: Thameslink livery, unbranded
319429: LM livery, LNWR branding
319433: LM livery, LNWR branding
319441: LM livery, LNWR branding
319457: LM livery, LNWR branding (with white cab ends)
319460: LM livery, LNWR branding
Class 350/1 - see post 599 on the dedicated Class 350/1 refurb thread.
350101: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished).
350102: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, unrefurbished).
350103: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350104: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, unrefurbished). At Long Marston for corrosion repair & refurbishment (again!)
350105: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350106: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished).
350107-109: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350110: LM "Project 110" livery, LNWR branding (no corrosion repair, refurbished)
350111-114: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350115: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished).
350116: LM livery, LNWR branding (no corrosion repair, refurbished)
350117-122: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350123: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished).
350124-128: LM livery, LNWR branding (no corrosion repair, unrefurbished)
350129: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished)
350130: LNWR "undercoat" livery, awaiting full LNWR livery & branding (corrosion repair complete, refurbished)
Class 350/2 (due to leave the franchise upon introduction of Class 730s)
350231: LNWR "outgoing" livery.
350232: LNWR "outgoing" livery.
350233: LM livery, LNWR branding.
350234: LNWR "outgoing" livery.
350235: LM livery (with BTP wrap), LNWR branding.
350236-238: LM livery, LNWR branding.
350239: LNWR "outgoing" livery.
350240: LNWR "outgoing" livery.
350241-243: LM livery, LNWR branding
350244: LNWR "outgoing" livery.
350245: LNWR "outgoing" livery.
350246-251: LM livery, LNWR branding.
350252-254: LNWR "outgoing" livery.
350255: LM livery, LNWR branding.
350256: LM livery, LNWR branding.
350257-259: LNWR "outgoing" livery.
350260: LM livery, LNWR branding.
350261: LM livery, LNWR branding.
350262: LNWR "outgoing" livery.
350263: LNWR "outgoing" livery.
350264-266: LM livery, LNWR branding.
350267: LNWR "outgoing" livery.
Class 350/3 - all reliveried into full (revised) LNWR livery with 1st Class stripe
350368: Full LNWR livery with "Resorts World Birmingham" advertising branding
350369: Full LNWR livery with "Edgbaston Cricket Ground" advertising branding
350370: Full LNWR livery with "Cadbury World" advertising branding
350371: Full LNWR livery with "Birmingham Airport" advertising branding
350372: Full LNWR livery with "Visit Liverpool" advertising branding
350373: Full LNWR livery with "Birmingham Hippodrome" advertising branding
350374: Full LNWR livery with "Liverpool Airport" advertising branding
350375: Full LNWR livery with "Madame Tussauds" advertising branding
350376: Full LNWR livery with "Wizarding World of Harry Potter" advertising branding
350377: Full LNWR livery with "RSC: Visit Stratford upon Avon" advertising branding
Class 350/4 (units leased to TPE in bold)
350401: Full (revised) LNWR livery with 1st Class stripe. Refurbished. Large unit no's.
350402: Full (revised) LNWR livery with 1st Class Stripe. Unrefurbished. Large unit no's.
350403: Full (revised) LNWR livery with 1st Class Stripe. Unrefurbished. Large unit no's.
350404: Full (revised) LNWR livery with 1st Class stripe. Unrefurbished. Large unit no's.
350405: Full (revised) LNWR livery with 1st Class stripe. Unrefurbished. Large unit no's.
350406: Full (revised) LNWR livery with 1st Class Stripe. Unrefurbished. Large unit no's.
350407: Full (revised) LNWR livery with 1st Class Stripe. Unrefurbished. Large unit no's.
350408: Full (revised) LNWR livery with 1st Class Stripe. Unrefurbished. Large unit no's.
350409: Still with TPE, in TPE livery.
350410: Full (revised) LNWR livery with 1st Class stripe. Unrefurbished. Large unit no's.