Ah, the vegetable terrine. I have a 1980s recipe (which I think I cooked once) for such a beast, although it was layered vegetable purees, rather than the individual veg.
Aspic was certainly popular in the 19th and early 20th century. I cannot recall seeing it in the UK although I was served a “tomato aspic” in 2016 at a restaurant in Vicksburg, MS.
Oh, and as for the steak pudding there’s nothing historical about them. Still very common in the UK - the steak one’s a staple of fish & chip shops (usually made by a compnay called Hollands). And a trendy offering in gastropubs - I had one a few weeks ago, filled with venison, pheasant and rabbit. That entry on the list is an advert for Atora, the manufacturers of the suet - still our major producer. I always have a packet in the cupboard, usually for dumplings for stew. The product was invented literally just up the road from me, in Openshaw, in sast Manchester, 1893. Production continued there until 1974.