Learn Farsi: ثانیاً، آن‌ها اطلاعات را طوطی‌وار تکرار می‌کنند. - Secondly, they repeat the information parrot-like.

It acts as an adverb of manner here, describing how they repeat the information (mechanically, like a parrot). The similitude suffix -وار can create both adjectives and adverbs, but when describing the manner of an action, it functions as an adverb.

Could we use the other similitude suffixes, -آسا or -مانند, instead of -وار here?

You grammatically could say طوطی‌مانند or طوطی‌آسا, but طوطی‌وار is the established collocation (natural pairing) for this specific idiom. -مانند is often used for literal, physical resemblance, whereas -وار is highly preferred for describing figurative, behavioral mannerisms.

Why is there a half-space (nim-fâsele) used in طوطی‌وار? Is it required?

Standard Farsi orthography uses a half-space before suffixes like -وار to keep the base word and the suffix visually distinct. While you might occasionally see it written as a single connected word (طوطیوار) in informal typing, using the half-space is the correct and much more readable choice.

How is the ending of ثانیاً pronounced and what is its function?

It is pronounced with an '-an' sound (sâniyan). The ـاً ending is the Arabic 'tanvin' marker, which Farsi borrows heavily to turn nouns or adjectives into adverbs. Here, it turns the Arabic word for 'second' into the adverb 'secondly'.