user3750: I know that a coinbase transaction must have one input, but can it have more than one?

user5406: No, coinbase transactions must have exactly one input, one with a coinbase field instead of referencing a UTXO to spend. Additional inputs are not allowed.
See also this related topic which describes more requirements of coinbase transactions: Does a coinbase transaction's input field have a VOUT field? (H/T RedGrittyBrick)

3750: <p>I know that a coinbase transaction must have one input, but can it have more than one?</p>
 5406: <p>No, coinbase transactions must have exactly one input, one with a coinbase field instead of referencing a UTXO to spend. Additional inputs are not allowed.</p>
<p>See also this related topic which describes more requirements of coinbase transactions: <a href="https://bitcoin.stackexchange.com/q/113392/13866">Does a coinbase transaction&#39;s input field have a VOUT field?</a> (H/T RedGrittyBrick)</p>
