Can I connect to Litecoin, Dash, BitcoinCash, Doge, etc. RPC with Bitcoin RPC client? I want to set up a few nodes for different Bitcoin-derived cryptocurrencies and regularly query them for data via the JSON-RPC API.

The thing is: I can't find much information on any other RPC API except for Bitcoin one. I'm assuming it's because all the Bitcoin-derived cryptocurrency nodes have the same API. So, can I just use, for instance, Python Bitcoin JSON-RPC client to connect to all of them just by changing connection strings?   

Sorry for the sloppy wording and stuff. I'm just stunned that there's so little information I was able to find.
Yes, you should be able to use a Bitcoin JSON-RPC client to interact with JSON-RPC servers for other cryptocurrencies if they are using software that is based on Bitcoin Core (which most are). Such JSON-RPC clients and libraries don't really have anything in them that is Bitcoin specific; they just handle the connection to the RPC server for you and return you the JSON formatted result.