Is it proper to say spaghettis for more than one spaghetti noodle? What about macaronis as a plural for more than one macaroni noodle?
No, we would use spaghetti, linguini etc. We would refer to a one spaghetti noodle as "a piece of spaghetti" perhaps. On the other hand we would refer to a noodle versus noodles. In the UK noodles is more commonly used for asian foods whereas Italian we would lump under pasta - and UK pasta is sadly often lumpy ;-)
However, Macmillan lists both pizza and lasagna as countable/uncountable, but doesn't elaborate. (Merriam-Webster lists pizzas as a valid plural of pizza, and notes that the plural of lasagna is lasagne.)
It's done very much on a case-by-case basis: some words follow the Italian singular/plural, but many don't.
Generally pasta things like spaghetti, macaroni, linguini are used for the uncountable (although it's linguine in italian.) For a single piece, you say "a piece of ...".
However, we say one pizza and two pizzas (not two pizze). And we say one panini and two paninis, even though in Italian panini is already plural and a single is panino