Is everyone able to see them or just me?
Everyone. What the point otherwise?
How long those extras (models / emoticones / etc) last?
Each bonus lasts forever. Anyone who obtains one will have it while playing DotA Allstars by DracoL1ch.
Is there any restrictions on using of bonuses?
The only restriction is your ingame nickname. Make sure that's we're talking about ingame nickname, not your login, username or anything else. The nick other players see when you're playing DotA.
It must contain standard symbols only. Use this page to check your nickname.
What if I want to change nickname later?
You can send me a message via e-mail. You have to tell me your previous nickname, the new one, and email which has been used for donation (so noone else can steal your identity by faking your message).
How do I activate bonus model?
Just pick the hero, it will always have new skin and effects while you're holding it.
How do I activate emoticone?
Type text related to emoticon into chat. You can type it with "-" sign in front, like "-lul", so it won't appear on chat but emoticon will still be visible for everyone.
When I will receive bonus?
Once I see the donation and your nickname. You have to give me your nickname somehow, via message with donation or via email. My timezone is GMT+5, so at night time I won't be able to instantly toggle it.