So if I add applications to my ledger for different coins does my recovery seed get me back access to all those coins?
Yes, the same recovery seed can be imported in any software/hardware wallet to give you access to the coins you have in case your hardware wallet breaks or Ledger no longer exists. Importing it into a software wallet is not recommended though because you lose the protection a hardware wallet offers by default.
I am confused because I used my pc to add accounts to my ledger, but when I used it on my phone those accounts did not show up. I had to also add those accounts on my phone and then they showed up with the coins in them.
Anytime you recover your wallet from seed, you will need to manually install each app on your Nano, scan, and add all accounts in the portfolio tab. That portfolio is only visible on that device you added it to.
So I was wondering if I lost my device if I would have to remember all the coins I had on there and add then as new accounts to get them back rather than just having the recovery seed?
Exactly. Let's say you have BTC and ETH on your Ledger. If you only install the BTC app and add your BTC wallets, your portfolio wouldn't display your ETH stash unless you do the same for ETH.
Your recovery phrase "unlocks" your access to whatever funds that are tied to your Ledger device. However, when you are done importing your private key into a new ledger device (assuming you lost your previous one), you'll have to manually add the accounts - cryptocurrencies - that had balance on them (Ledger doesn't automatically add them after an import process).
Just a correction. You aren't importing private keys into a Ledger Nano or Ledger Live. There isn't such an option to do that. You can only work with and recover from seed. There are advanced 3rd-party methods to find private keys but not from the device or LL.