does electrum support all of these coins?
No.
If not can you tell me what software should i use for each coins?
To everyone
1: Stop asking altcoin questions in this thread and questions that the first Google Search can easily answer, like "Monero Wallet".
I just the safest possible..
Anyone who is asking any questions in this thread will not be able to have a setup that even remotely resembles "safest possible". "Safest possible" does not involve with you asking basic questions. In order to have such a setup, extensive experience and knowledge is require. Time to get some education on cryptocurrencies, no?
Plus,if my offline computer crashes.. what are my options to recover my coins?
Backup the wallet files or seeds depending on the type of wallet on multiple machines/locations.
[1] Answers to such will be swiftly deleted.