I'm interested to dig a little into semantics- is the line, or the route, to be fully electrified?
The former I'd take as a plan to electrify despite the Standedge/Mossley difficulties- the latter I'd interpret as wires Hudds-Marsden, and thence an electrified NPR line to Piccadilly, but Marsden-Stalybridge remaining a diesel (or battery?) island.
There's an IRP decision in principle to electrify MML and TRU in full, despite both being "paused" for several years.
Some bits were well advanced in planning terms and are being delivered now: Kettering-Market Harborough, Colton Jn-Church Fenton and Man Vic-Stalybridge.
Other sections will follow once Network Rail has established the costs and gained DfT approval for the spend.
Huddersfield-Dewsbury is the first of those, maybe getting approval in 2022 after the TWAO public inquiry.
The NPR new lines are right at the start of planning, so it will be a year or two before alignments and costs can be proposed.
NR also has to plan (electrified) routes between Sheffield and Leeds, and between Liverpool and Warrington BQLL, for HS2/NPR traffic.
TRU is also supposed to be suitable for freight which means gauge clearance as well as wiring.