Onomatopoeia

Source: सुहासः

My preference is to avoid modernisms and try to reuse existing words and word construction paradigms as much as possible. Especially if new coinages clash with established ones. For instance, हा हा has the established meaning of sorrow, so I would not use it in the book for laughter.

Most onomatopoeia in Sanskrit is outside of the main canon (Kalidasa, Bana etc.). The frequency is greater in Jaina literature and in authors like Rajashekhara who engaged with Prakrit. The frequency is greater in Prakrit, and even greater in Apabhramsha which really loves onomatopoeia. As translators into Sanskrit, we should be drawing upon the entire Sanskritic tradition to find the words that we need. This is a big list of onomatopoeias found in the Mahapurana of Pushpadanta. It should also not be difficult to grep through a text corpus to make a list of such usages.

One option for PLIP PLOP PLIP! PLIP PLOP PLIP! might be घव घव घव घव…, 

(taken from an Apabhramsha usage for the sound for water. घवघवन्ति जे जल-पब्भारा [घवघवन्ति ये जलप्राग्भाराः], पउमचरिउ of Svayambhudeva). 

bzzz… squwaack… psheww! could be translated with something like क्रेङ्…कटकटा…टसटसत्! 

[from क्रेङ्कार, कटत्कार and टसत्कार]

I like your coinage पेङ्कार for horn.

The Panini sutras to be kept in mind for such constructions (afaik) are 1. अव्यक्तानुकरणाद्द्व्यजवरार्धादनितौ डाच् 2. अव्यक्तानुकरणस्यात इतौ 3. नाम्रेडितस्यान्त्यस्य तु वा