There's no problem or danger with importing a wallet as watch-only it's the best thing you do if you only signing transactions on an airgap device like a phone.

Coin control is what you need if you don't want to spend any unconfirmed transaction check the image below you can also ignore and don't add other coins if you don't want to spend them all(Confirmed or not).



Once you add a confirmed transactions that's the only coins you can spend on the send tab.