Can you have more than one air tag paired to a iPhone

Yes. And you can name them so that you know which is which when tracking. See information in Set up your AirTag using your iPhone, iPad, or iPod touch - Apple Support

Not directly related to your question, but you should be aware that most CR2032 batteries from major manufacturers have a "bitterant" coating on the battery, which while designed to discourage a child from swallowing the battery, can also result in poor electrical contact between the battery and the AirTag.

If you have a new battery installed, but get a "low battery" reading, it is probably because of the bitterant coating.

You can use some pressure to rub hand sanitizer on the battery and then wipe clean with a soft cloth.