I think the North West enhancements were basically covered by the new 350s, slightly more than half of the 319s (with the other share going to FGW) and then cascading the DMUs released on to other services - which will mean Pacers and 150s would not be replaced by cascaded 319s. Although, there are now issues relating to when the 319s will be ready to cascade.
There are then extra EMUs now required for Yorkshire locals and North TPE electric services.
I think were are looking at additional rolling stock orders overall, the question will be the rolling stock balance between EMU and DMU and which operator has to lease the more expensive new rolling stock. There isn't an efficient obvious solution as regards a TOC having all new identical EMUs without leaving some existing in store / scrapped.
FGW (or successors)
Will probably need at least another 4x 319 to operate the branch lines (if they continue to operate as branch lines) or even more units if they operate them to Paddington due to yesterday's additional electrification announcements. The HLOS also outline clearance work for cascaded DMUs in the Bristol area i.e a new home for 165/166 which with some resulting moves will release some 15x to eliminate 14x.
As FGW or successor will have new IEPs, new "stopping" EMUs at the same time is unrealistic.
Chiltern as the nominal EWR operator:
Will need some additional rolling stock which will probably be a mix of cascaded EMU and DMU again 319 and 165/166. New rolling stock for Chiltern is unrealistic until they electrify the rest (or most of). They already have some of the most diverse rolling stock of any TOC especially as they are the smallest.
ATW or successor:
Lots of 315s but not enough spare for all the valleys even after Crossrail leaves a few more spare, so some DMUs under the wires?
Walsall and Rugeley Trent Valley will also need some EMUs
Northern /TPE
Even with some services going over to EMUs there won't be enough 319s (as per previous threads) so some DMUs under the wires or new EMU order with some cascades? The only other spare EMU coming up I can think of would be the ex Heathrow connect 360s when cross rail takes over but there are only 4 of those.
Then there are the non electrified routes being strengthened e.g.
"Leeds Harrogate strengthened by revised train formations and additional Leeds Horsforth shuttles." from the DfT HLOS illustrative options document which would mean at least 4 extra DMUs needed and there are other similar examples too.
Unless more electrification is announced for early CP6 (i.e. Leeds - Harrogate (-York) and Leeds - Sheffield or more north west for starters) and some short term (2-3 year) derogations for DDA on 14x and some 15x (153?) there will have to be an additional DMU order as well - the question is how large.