I have a trezor. The private key is on the trezor and along with the public key points to the location on the blockchain of my bitcoin? Yes/no
No. The "seed" is on the Trezor. The seed is used to generate all the private/public key pairs that give you control over certain bitcoins.
on coinbase, my private key is stored by coinbase, has separate private and public keys and if I kept bitcoin there, yes/no
it would be in an entirely different location on the blockchain?
Yes. If your coins are in different addresses, with different private/public keys... they are separate from the coins controlled by the Trezor private/public keys.
The seed is just a complicated as hell password that allows me to access the trezor, and the public and private keys? Yes/no
No. The "seed" is actually just a (VERY) large random number. The "seed mnemonic" (aka 24 words for Trezor) is a method to turn the "seed" number into a series of words that are a lot easier for humans to write down and store without making mistakes (it also includes a very basic checksum to help prevent errors). What the seed/seed mnemonic allow you to do, is easily recreate the entire wallet along with any address it has generated. Effectively, it is a complete "backup" of your wallet, in just 24 words that you can write down on a piece of paper and store securely offline.
I can make a different seed (I don't actually want to) without affecting the public or private keys, or the location of my bitcoin on the blockchain? Yes/no
Depends what you mean by "affecting the public or private keys". If you create a different seed, it will generate a completely different wallet... with different private/public keys and addresses.
Your bitcoins will continue to stay with your previous private/public keys and addresses, as your bitcoins will NOT move from their current private/public keys and addresses unless a transaction is created that moves them.
So, if you created a different seed, without "backing up" your previous seed, you would lose access to the coins controlled by the previous seed... as your Trezor would now be using new private/public keys and addresses and have no access to your old ones.