does פלפל refer to capsicum, chilli and actual pepper (corns)? Or just some of those?
It really could be any of the above. פלפל שחור = black pepper, פלפל חריף = chili pepper, פלפל אדום/ירוק/כתום for bell peppers depends on their color.
Bell peppers are often referred to as גָּמְבָּה gámba though.
That usually implies red ones specifically, in my experience.
Note: in actual spoken Hebrew, rather than prescriptively ‘correct’ Hebrew, people pronounce it pílpel (pl. pílpelim).
الفلفل لا يحرق very close to arabic
Is this hot like spicy or hot like warm?
It was pronounced pilpil once, but now its pronounced pilpel. Which one is correct?
The correct pronunciation is pilpel.