Maximizing Fastpass

We are visiting WDW for 3 days in May with my family of 4 plus my parents. So there will be 4 adults, my 5 yr old daughter, and my 2 yr old son.
We’ll be visiting Epcot on Thursday, Magic Kingdom on Friday, and Animal Kingdom in the morning with Hollywood Studios on Saturday. We’ll have to take the 2 yr old back to the hotel in the afternoon for naps.
We only have 3 days at the parks so I’m trying to maximize our time. I read about using the rider swap + fastpass to maximize our time. - How to use Rider Switch at Disney World
Would it be a good idea to use two sets of fastpass groups so we sample all the good attractions using rider swap?
Group 1 my wife, Grandmom, and daughter
Group 2 me, Granddad, and son

Without this I don’t think we’d be able to get to ride things like Sourin’ and Test Track during the same morning in Epcot.

Thoughts?

Is you daughter tall enough to ride? And your son too short?

She is 40" right now and will probably be taller by our trip.

He is 36" currently but I don’t see him hitting 40" before the trip

Yes, it’s a good idea. We did it all the time and it’s intended by Disney. Half your people get FP’s for Soarin’ and then the rest ride by RS. Half your people get FP’s for TT and then the rest ride by RS. The child doesn’t even have to be under height, as long as he/she doesn’t want to ride and can’t be left alone.

So if you want to ride soarin and test track…soarin: mom, dad, DD have fp then rider swap: granddad, grandma, DD (DD would get to ride twice everyone else once)// test track: granddad, grandma have fp then mom, dad, DD would rider swap

That should work as long as they don’t require everyone to have fp some cms ask.
This could be a good idea but then you won’t be able to get FEA for which is something everyone could go on so depends on priorities. You could Rd it.

We did this last month and it worked really well for us. The only time we got push back for the second group not having a FP was on 7D but they let us in with a “just this one time.”

We did it something like 15 times over the course of our week long trip in December including FoP, SDD, and 7DMT and never got any trouble.