dat file in electrum i ever know just this thread, for the spesific location i do not know. just read https://bitcointalksearch.org/topic/how-to-import-electrumdat-file-created-with-181-in-electrum-19-325364
that is an old version of Electrum, there is no wallet.dat file anymore. the wallet file is now in a JSON format with the name Default_Wallet and without any file type.
@OP
if you can't simply find the wallet file of each wallet then you need to find the documentation of each wallet and read that.
for example here is for Electrum which tells you where your wallet file is depending on your OS
http://docs.electrum.org/en/latest/faq.html#where-is-my-wallet-file-located
Quote
On Windows:
Show hidden files
Go to \Users\YourUserName\AppData\Roaming\Electrum\wallets (or %APPDATA%\Electrum\wallets)
On Mac:
Open Finder
Go to folder (shift+cmd+G) and type ~/.electrum
On Linux:
Home Folder
Go -> Location and type ~/.electrum
Show hidden files
Go to \Users\YourUserName\AppData\Roaming\Electrum\wallets (or %APPDATA%\Electrum\wallets)
On Mac:
Open Finder
Go to folder (shift+cmd+G) and type ~/.electrum
On Linux:
Home Folder
Go -> Location and type ~/.electrum
