Access to Neasden depot

I'm a bit rusty as it's over 2 years since I spent some time there so I am rusty with the particulars but yes trains can be routed from Neasden Jubilee in the depot, on sunday nights trains were booked to cross over the N/B jubilee and S/B met. The move involved was possible because the jubilee signalling system has some degree of control over the met line signals. I remember a train (track recorder) was directly routed from the outlets at klondyke by the Jubilee without needing any involvement from Baker street

From the northbound they can only go into Klondyke, up to the north dock to then reverse and stable in the main depot. For that reason (time consuming!) it is quite rare although I have known it done for line training purposes. You are probably correct that WTT13 does not include such a path as I THINK the Charing Cross "rusty rail" path(s?) now run up to Wembley Park, then siding and thence depot.

On a similar theme about Jubilee trains crossing the Met line, on Mon to Wed after 22:00 due to the engineering work on the Met, Jubilee line Neasden stablers are having to route "over the top" across the southbound Met, as reversing Met trains are using the "dip." This is sometimes causing delays to the Jubilee as Met signallers tend to prioritise their reversers which look as though they run down to Neasden, reverse back north up Klondyke then the "dip" to Wembley Park northbound.

So to answer the original post, yes it is possible although I don't know the exact protocol for how the signalling / TBTC interface is managed.

Not during traffic hours. There are no longer any standard type signals.