1. Not Really :l you can try but in some languages you are fast on the end of the language.
2. Not Really you just need a good knowledge about Packet Handling, Session Handling etc to be sure that your server never crash when more as 100 people are on the Server
1) yes technicly you should be able to développe all with any programming language (rocket guidance system for exemple) but with some language its like Try Killing a bee with nuclear bomb...
2) all dépends on your knowledges