Nice job. The kit betrays its age, and the roof has a nasty contour.
Btw, the E116 had fishbelly bogies. (The K's kit, as supplied, does contain them.)
Not sure I believe the upper drawing of the E19 - look at the compartment spacings of the side elevation view.
Here's an E19:
https://www.warwickshirerailways.com/gwr/gwr-mra453.htm
Yes, three E40 pairs. Perhaps one was a spare, being cleaned, but I wouldn't be surprised if they were used on the Falmouth branch, or perhaps the Newquay-St Blazey services.
Here's an E40 pair sandwiching a shorter coach (6-wheeler brake compo?) at Carbis Bay. It is c pre-1913, because of the lack of loco topfeed, so the stock is either in brown or possibly crimson lake. Loco and stock are very clean and shiny, but the coach rooves are already a dull grey.
An E40 pair was often used on the St Ives branch. This pic is 1928. Not sure when the E40s disappeared, but E116s and of course (later) the ubiquitous E140s predominated.
Judging by the compartment spacing, I think they are an E40 pair, i.e. a 'B-set' (two brake compos). The inward/outward guard's doors is an interesting quirk - never noticed that before - but it seems the official diagrams are not consistent.
I wonder what's on the Worsley etch!
I think it's a lubricator for the vacuum pump. The mounting and position seem to have varied, with many being in a more forward position, like the one on 2999.
This one, on 2901, has an inverted U-shaped mount.