Long term capital gains on SOME not all cryptos?

I wish I could answer in greater detail. I have not received or created a tax report from Coinbase yet. Coinbase might report nothing but provide you with all the necessary information in your report. If the report is a 1099-B, then yes, they reported to the IRS. Since they refer to it as a tax report I assume it is not.

If your trades are over a certain volume / dollar amount they may also report it but it that case you would receive nothing. It would be no more than CB notifying the IRS of a person of interest. I believe that is the compromise CB made during the last bull cycle (2017) when the IRS demanded CB release all user information.

Since trading crypto is the equivalent of trading stocks the same rules apply. You can elect FIFO, LIFO, HIFO methods to determine which purchases will be chosen first when you sell. Sells after positions age 366+ days are long term, any prior are short term. So if you HODL and day trade BTC a segment of BTC will be long term and a segment short term. If you only HODLed BTC and day traded everything else, only BTC would be long term.

CoinBase will issue some forms but ultimately you're responsible for filing your taxes. Whether your gains are short- or long-term is irrelevant.

For the 2020 US tax season, Coinbase will issue the IRS Form 1099-MISC for rewards and/or fees through Coinbase.com, Coinbase Pro, and Coinbase Prime.

Non-US customers will not receive any forms from Coinbase and must utilize their transaction history to fulfil their local tax obligations.

What are my crypto tax obligations for the 2020 tax year?
If you have sold or converted crypto in the year 2020 and are subject to US taxes, you are required to report your gains/losses to the IRS.

To learn more about how US taxes and crypto work, please visit: http://coinbase.com/bitcoin-taxes.

Does Coinbase provide 1099-Ks?
As of the 2020 tax year, we will not be issuing Form 1099-Ks for trades on Coinbase.

Does Coinbase provide 1099-Bs?
We do not issue Form 1099-Bs.

https://help.coinbase.com/en/coinbase/taxes-reports-and-financial-services/taxes/coinbase-tax-resource-center