Gujarati: अाओ रास खेलने के लिये

Can you help me understand how declensions would work in the following sentence in Gujarati? I'm not sure what happens to the verb in this sentence.

अाओ रास खेलने के लिये

खेलना = રમવાનુ?
लिये = માટે

So, would this sentence be: અાવો (તમે) રાસ રમવાનુ માટે?

खेलने "khelne" (in Hindi) = "ramvane" in Gujarati.

Pyramids of Egypt

What is the Hindi word for "Pyramid"?

The word in Hindu for Pyramid is "Pyramid". It comes as it is in Hindi. Or one can use शुंडाकार स्तंभ or शुंडाकार भवन.

Contagion in Hindi

Contagion is the word used in English to denote the spreading of germs by direct or indirect contact. The simple way of conveying it which comes to my mind is ''biimaarii phailnaa'' but it doesn't seem satisfactory because it is not specific enough. Can you translate the sample sentence ''The risk of contagion is higher in schools and public places'' into Hindi please?

"Sankraman" (संक्रमण) is the Hindi word for it. Here is the translation:

''The risk of contagion is higher in schools and public places'' => संक्रमण की आशंका स्कूलों और सार्वजनिक स्थानों में अधिक है.

Or, "The danger of contagion is higher in schools and public places' => 'संक्रमण का ख़तरा स्कूलों और सार्वजनिक स्थानों में अधिक है.

ऋ not pronounced as रि?

I read this at a place: "As for the ऋ, many Hindi speakers do pronounce it correctly, and even if not always correctly, they pronounce it differently from रि."

Is the above statement correct? Can you please explain to me how the Hindi speaker's pronunciation differs from ri or ru or some corruption of the two because I didn't agree with the above statement.

I agree with the statement "As for the ऋ, many Hindi speakers do pronounce it correctly, and even if not always correctly, they pronounce it differently from रि." In fact most Hindi speakers make a difference between the two.

I don't know how to make you hear, but tongue movement is different in the two ri's. In ऋ, it goes much behind while in रि it remains near the front (of the mouth).

Sansanii सनसनी

I was looking for a word that could be translated as "sensationally" and the word I've come across is sansanii. Can the word "sansanii" be used with a negative conotation?

"Sansani" सनसनी is most of the times used in this negative connotations; so you can go ahead and use it.

driver / chaalak रिक्शाचालक

In a BBC Hindi article I found this word: रिक्शाचालक rikshaachaalak. Is this word used in colloquial Hindi speech?

Rikshachaalak (रिक्शाचालक) means driver of Rickshaw and is a very commonly used word in Hindi. It is not of new or recent usage but a pretty old one. You can speak it and will be understood by Hindi speaking population. 

Parii परी Vs Jinn जिन्न

In Urdu, we use Parii परी and Jinn जिन्न to mean the same thing. Is it same in Hindi also?

In Hindi Parii परी and Jinn जिन्न are not the same. Parii परी is considered essentially female while Jinn जिन्न can be both, may be, but mostly used for males. As such in Hinduism, souls don't have any gender but when souls are stuck without taking rebirth, hence called Atma आत्मा, Jinn जिन्न or Pret, or things like that, a gender is used to describe such souls. Yet in truest form a soul doesn't have any particular gender in Hinduism.

"rabri" or "raabri" in Hindi

Is it "rabri" or "raabri" in Hindi? Is it spoken also as "raabri" in all parts of India?

It is spoken both as Rabri रबड़ी and Raabri राबड़ी even in Hindi. 

I have heard it everywhere; some people speak रबड़ी and some speak राबड़ी and both are correct.

आप लोग हाज़िर हुए Vs आप लोग हाज़िर थे

आप लोग हाज़िर हुए Vs आप लोग हाज़िर थे : Any difference and which is better usage?

आप लोग हाज़िर थे (aap log hazir the) indicates towards a statuesque meaning, "you people were available". 

आप लोग हाज़िर हुए  (aap log hazir hue) indicates immediate state/status, or an event of appearing, meaning "you people became available"

Fursat me Vs Fursat se (फुर्सत में Vs फुर्सत से)

Can you explain difference in usage of फुर्सत में Vs फुर्सत से, if any?

"fursat me" फुर्सत में and "fursat se" फुर्सत से are used almost interchangeably, though at times fursat me is better and at times fursat se is better. 

"Fursat me" फुर्सत में indicates towards a "static" nature in which the person is at leisure, apparently for a long time.

"Fursat se" फुर्सत से indicates immediate attention towards the "present" time/status where the person is at leisure at present, may or may not have been like this for a long time.