I don't think Kamehameha would have ceded anything willingly, but if a deal with Great Britain was framed to him as an alliance, I could definitely see him taking them up on it. This might prompt British rather than American missionaries to arrive to Hawaii, and while these families would still create a base of white settlers, it would be one that sees the monarchy in a more friendly light and would probably be willing to keep it on the throne, resulting in a powerful political force to promote Hawaiian autonomy despite the (likely) loss of full Hawaiian sovereignty to Great Britain.