If I'll win that freeroll and 0.3 bitcoin, am I able to withdraw it even if I haven't deposted and my account is created 1 day ago?
I like that news about weekly freerolls but it would be better to offer small freerolls every day, for example 0.05 everyday freerolls.
Also, Can you buy chips while I am playing? Or only limited 1500 chip stack?
Yes whatever you win is unrestricted funds you can withdraw it all straight away even if you have not deposited and your account was created 1 day ago.
There is no chip rebuy or top up in this tourney, just your starting stack.
Good luck!