I'm wondering if something like decred time stamping service is used across bitcoin,ltc,zec etc the original bitcoin works and if they do someone could point me to that
Decred time stamping is a way to store an arbitrary hash on decred blockchain as "Proof-of-Existence". This has been part of bitcoin ever since day one and became popular when OP_RETURN outputs became common.
This is not related to what you are asking ahead.
because it seems like multiple chains would need to work together in order to be more secure from being corrupted.
Not at all. Take bitcoin for example, the thing that ensures the blockchain is not "corrupted" is the Proof of Work and that doesn't need another chain.
Seems logical as each chain wouldn't need to hold every block for every chains full data just a hash of the block.
It won't work. Decentralization depends on the principle of "don't trust; verify". Meaning you have to download and verify everything and in order for you to do that, there have to be other nodes that store everything and can provide you with the entire block, not just its hash. Those who don't store the blocks (only store the 80 byte header) are simplified verification clients (SPV for short) like Electrum.
