What is the status of Blue Labour in the real world?
It graduated from ThinkTankWank to 'maybe part of the direction of the Labour Party' for about 18 months from 2011 to 2012. Then Maurice Glasman, its de facto head spokesperson, went too far in his criticisms of immigration and the whole thing got dropped as being too racist. It hasn't been a thing since.
Parts of it were key to 'One Nation Labour', but that appeared to resonate for a while and then suddenly didn't, lasting only a year or so and being dropped by the time of the 2014 European elections.
It's now completely dead.
And the status of Red Toryism, by the way.
Has never really been a thing. Not even sure it deserves a wiki article. (Which, on looking at it, it does have but is mainly about other countries where it exists as a trend - which is fair enough.)
Well if Cruddas wins in 2015 there wouldn't be a leadership election and Corbyn would remain on the backbenches. Maybe some left-wing revolt in the Labour party?
If Cruddas pulls it off (as is implied by this whole setup), the discontented masses that bolted to Corbyn in 2015 wouldn't get into that state. There is no left wing revolt around Corbyn if Cruddas is PM and is taking steps to nationalise the railways etc.
Hm, if not Defence, maybe some other role in the cabinet for Jarvis? I'm thinking Spellar as well lands a spot.
You don't tend to get put into the shadow cabinet in the same term that you were elected in a by election. Jarvis could well position himself within blue Labour quite nicely but it's hard to predict what he'd do or be offered.
How would Corbyn fit in with all of this
As above, he wouldn't. His election is one of the flukiest, most butterflyable events in modern British history. He would remain a backbencher making noises about how Blue Labour was headed in the right direction on economics but wrong on social policy.