N English word for the Spanish pepper called Ñora

I would call it a custard, I think, if not only for want of a better word. A custard consists of milk, egg and a thickening agent i.e. flour, so it fits the description well enough.

It might sound a bit odd to English-speaking ears though. I think 'savoury custard' is probably more appropriate. I must admit I always thought moussaka et al was topped with a white/bechamel sauce; I'm pretty sure that's the more common topping in 'the West'.

As for the dishes themselves, I'm not sure if there is a catch-all English term for them - 'pasta bake' is an English version of the Italian pasta al forno, but that obviously only applies to dishes that use pasta.

In Britain (and France), the large purple varieties are known as aubergines. Other (pale and/or small) varieties aren't usually found outside of Asian supermarkets, where I imagine they are still referred to as brinjal.

The name 'eggplant' is used in the US, Canada, and the Antipodes, mainly because the lighter varieties are more common there, which arguably have the colour of eggshell.

They are, however, all just different varieties of the same plant, like yellow and red tomatoes.