Is it possible to make this recipe in a large glass trifle bowl instead of individual servings? If so, can I triple the recipe to accommodate the...

Chops, pending the recipe author response, here are a couple thoughts for you
1) I remember learning a rule of thumb that it's best to only double or halve a recipe, not more or less (old wives' tale - maybe. But several websites are advising similar...to make double batches of some things, single batches of others). So maybe make one double and one single batch to get 3x the original pudding.
2) Most trifle bowls that I've seen aren't heat proof, so I would fear cracking the glass if you pour hot pudding from saucepan to trifle bowl. Rather, suggest you make the pudding in heat-proof bowls, chill, then mound attractively in the trifle bowl to serve.