I would go with what is suggested unless you're just going for the oem fit and finish of a real install. Being spring break is around the corner I'm guessing not too much time to order things and get it done. I'd go for an an adapter such as what is linked above, with the highest output you can find...that 60w isnt probably too common locally sourced though. Most are 30w and will do 18/12w on the 2 ports.
Most modern devices will charge at 12, 15 18, or 25 watt with an outlier or two above that. Generally speaking nothing above 9-15w is usually necessary for anything other than rapid charging. Throw some 10' cables on and route them under door sill trim or carpet to get back to 3rd row somehow and not make a trip hazard. Broken tablet/phone ports are costly. My note 20 ultra can charge with as much as 45w and be done in 35min but charges fine from the 12w output on my radio that is routed into my console, just takes longer which is perfectly fine for a roadtrip. The iPad pro is supplied with a 20w charger for fast cshrge but also charges just fine at 12w, albeit slowly.
Speaking from experience on this. Have a family of 6 as well, we drive everywhere and I used to install 12v goodies for a living. I plan to add in hardwired ports though it hasn't happened in 2 years so I need to get on that project. Mine will end up in the trays in the 3rd row and I plan to modify the panel on the rear hvac controls to accommodate a few ports as well. It's quite a bit of work due to the disassembly but will be much nicer than stringing cords all around.
