As a lifelong snorkeller my advice would be to forget about brands altogether and focus instead on fit.
With fins, ensure that the foot pocket accommodates the boy's growing feet both width- and lengthwise. Too loose a fit will lead to the fin falling off. Too tight and the result will be cramping. If he is between sizes (fins come in multiple sizes such as 5-7, not in single sizes), then select a fin that is slightly too large and use fin grips for security. As for blades, don't select fins that are too stiff for a young beginner.
Fit also matters when choosing a mask. The traditional way of choosing a mask for fit is to apply one to your face without using the straps, create a partial vacuum by breathing in through the nose and seeing whether the mask remains in place. You can never be sure, however, if there will be no water leakage until you try a mask in the water. Be sceptical about the mask recommendation "such and such a mask is guaranteed to fit all faces".
Take care when selecting a snorkel for a young person. National Standards for snorkels have distinguished between breathing tubes for adults and children since the 1970s. Here is a table I compiled from these Standards:
So ensure you choose a snorkel that is not too long or the boy may strain to breathe.
Finally, you use the word "travel" in your description of snorkelling gear, which always makes me shudder a little because it means that the airline unduly influences gear choice. What fits and suits the snorkeller, particularly when it is a young beginner, must be paramount. I've never been to Hawaii, but I understand that there will be plenty of snorkel rental outlets there so he may decide to leave equipment selection until he gets there. One of the recommendations in old snorkelling books is to borrow and try out gear from friends, which will at least inform choice when getting round to purchasing before departure.
And just to reinforce the point, remember that fit is the most important factor, not colour or branding!
