For JQ you will get no benefits of your OW status, no miles, lounge, luggage etc. so I suggest as above you call JQ and specifically ask on luggage. Do not confuse them with the QF segments etc. JQ will only check you bags to PER, you will need to collect there and recheckin

for QF, as Dave says can you take more in carryon, it is a link flight so likely they will check any rolly bags at the gate. For QF BA bronze I do not believe gets you extra luggage, but the equivalent QF silver gets 32kg, if you are only 2kg over, I would be tempted to try my luck, and if the self check machine asks for a payment, find a QF service person say you are silver so should have extra luggage and they are likely to override. (Or not depends on your charm and their willingness). Or just pay extra online with QF.

while you have one ticket, as it is JQ you loose a lot of the typical one ticket benefits.similar to vueling. Note it may have been easier to book QF all the way, even if it cost more. You can still make a change subject to a $99 fee I believe?

KF