Is it possible to use same synced blockchain with more wallets, deamons from different operating systems, eg. Windows and Linux? Of course, not in the same time.
Well, it depends on what you're asking.
I run my node on Ubuntu Linux. I have connected wallets from Linux, Mac, and Windows to the node running on Linux. Connecting at the same time shouldn't matter.
If you're asking about having some network drive that is just connected to your router, and you want to run
monerod from various computers around the house by using the
--data-dir flag, and the computers will basically take turns at syncing the blockchain, that would probably work, as long as you don't mix chip architectures (x86 vs ARM). It may or may not work across 32 vs 64 bit computers. In general, I'm sure there are reasons why this is not a good idea, like how LMDB would behave, so hopefully someone can provide a more technical response to address that aspect.