Is it more private to use Monero on Tails with a remote node then it would be to use Electrum (with BTC) on Tails?
When using Tails (so Tor for your internet traffic) it is "safer", from an IP tracking perspective, than using clearnet. From an IP tracking perspective there is really no difference in safety between using an SPV wallet such as Electrum or the Monero wallets with a remote node, they both work in a similar fashion and what you are doing by using Tails (so Tor) is trying to make tracking your internet traffic difficult. Of course, using Monero instead of Bitcoin has significant privacy advantages.
So in summation, yes, using a remote node (Monero) is more private than using Electrum (Bitcoin), because Monero uses stealth addresses (so hides your address) and hides the amounts (Confidential Transactions). Using via tor/i2p adds further privacy by hiding your IP address (whichever you use, Monero or Bitcoin).