Do I qualify for the $20 if I already have a Youthsaver account and/or a Kit account?

Yes, you still qualify. Existing Youthsaver account holders and/or existing Kit customers are eligible as long as you link your child’s Youthsaver account to the Kit app during the campaign period, meet all the eligibility criteria and as long as you haven't already linked a Youthsaver account to Kit in the past.