Combine chicken with onion, celery tops, curry powder, salt, pepper, and water in a large saucepan; cover.
Simmer 45 minutes, or until tender.
Remove chicken from broth; cool until easy to handle.
Strain broth into a 2-cup measure; skim any excess fat, then add milk, if needed, to make 2 cups; set aside for Step 5.
Pull skin from chicken and take meat from bones.
Cut meat into bite-size pieces.
While fixing chicken, cook noodles and peas in separate saucepans, following label directions; drain.
Combine with chicken and almonds in a buttered 10-cup baking dish.
Beat eggs slightly in a medium-size bowl; stir in the 2 cups chicken broth from Step 2 and cream.
(This much can be done ahead.)
Pour custard mixture over chicken mixture, then stir lightly so liquid seeps to bottom.
Bake in slow oven (325°) 1 hour and 15 minutes, or until custard sets.
(Cover lightly with foil during last 15 minutes to keep top moist.) Garnish with diced red apple and coconut, if you wish.
MAKE-AHEAD NOTE: Cover chicken-noodle mixture in baking dish and custard mixture in bowl and chill.
About 1 1/4 hours before serving combine both, following Step 6; place in a cold oven; set heat control at slow (325°) Bake 1 hour and 15 minutes.