Although this thread was to give an idea about how 0 to 100 style binaries work not only on Nadex but in general but since your questions are towards nadex I will reply them accordingly.
1. Is there a commission payable for each contract ?
Yes there is a fees $0.90 per contract you trade but charged only if you win the trade.However the maximum fees at any one trade regradless the amount of the contracts you trade is $9.0 so whether you do 10 contracts or 100 your fees is capped at $9.0.
2. The expiry spread for AUDUSD shown in the vid is 4pips for 5min expiry. Can you provide a tabulation of expiry spread for other pairs with their relevant expiry TF?
3. What other expiry TF is available besides 5min ?
Answers to both of those questions can be found here http://www.nadex.com...-contracts.html
4. According to your observation, is there any deviation between mt4 quotes and the "indicative index" ?
Yes,as all the mt4 brokers have different price quotes at same time in the same way nadex and many of mt4 platforms does not have same price quotes.So please select a mt4 for charting which is closest to nadex indicative price.
5. How's the platforms's response during news releases ? Does it freeze?
No it does not freeze but during news its really hard to get into trade as sometimes there wont be any price quotes to enter a trade because of the fast moving market.But hey its always better to stay away during news lol
6. Besides other traders does the broker provide liquidity for the transactions and is there a ceiling limit for it?
Besides traders there are market makers who provide liquidity to the nadex contracts.Nadex itself dosnt do that hence Nadex dosnt manipulate prices or anything because its simply making money by the fees and dosnt care wjo loses who wins as the house dosnt have its money on stake.