Wanting to know if I’m exporting with my private key from metamask to a wallet will all contents of the MM account be exported? iE will the ethereum be exported along with my Theta token? Or would there be a different private key generated for both tokens. Thanks.
No assets will be moved. The process is only about registering your wallet to a different place. From the blockchain's perspective, nothing changes, since you will still be using th same private key to create transactions, and the same private key holds the assets.
So you don't need to explicitly move any assets (Ethers and tokens), they are wherever your private key is.
Just to note, if you export the private key and give it to someone else, they will then have the power to transfer all your assets. So please keep your private keys safe.