Is it possible to monitor all crypto-coins? Different coins have their own blocks and wallets, I want to build application to support multiple coins and my questions is Monitoring all coins possible(view transactions, get balance etc)?
You would need to install all of the coin daemons and scrape them for transactions using something like Abe, or your own custom solution using RPC commands.

If you are able to find an API which provides this information (I have yet to find one with a good amount of coins and reliable), then you could simply make calls to that; the only problem with using an API is that you are dependent on them and if they go offline, so do you.

My recommendation, get a VPS and start installing some coins :)