Went on a four day trip with my wife and six year old. First week of December last year.
We did Genie + and park hopper.
For our small group, park hopper was a good thing
for my son. He wanted to do webslingers every day. Which is fine, but we'd be bouncing between parks which added a lot of steps. If we had told him "One park a day", we could've planned for just the one park and maybe optimized more? Added in my son wanted me to carry him on my shoulders and it was a lot. Happy to do it! But still a lot.
If I told him one park a day, he'd just accept it.
For a larger group, that's a lot of back and forth that's unnecessary. You will not have a bad time without park hoppers. It'll make a lot of the trip easier.
Park hoppers for older people are better because DCA is normally not a full day park and you can go back to
Disneyland proper. There's just not enough there. But for our 6 year old, there was the redwood Creek challenge trail area. He loved it. We spent hours there. At first we were like "come on dude... There are rides!" but it was his trip, too and he was getting so much enjoyment.
This means 2 days DCA and 2 days Disneyland single park tickets would work for us. Also one of the DCA days could be downtown Disney time, too.
Now add in reservations! Gotta get everyone from one park to the other for a meal? Difficult. Unnecessary.
Genie+ lightning lane is a must. While it is expensive, you are gifting everyone a fun day at the park. You could be gifting them hours of line standing instead. Even at lower crowds the lines were long and we just walked past it with LL. Rides kept breaking down, so people would wait in line only to be told to come back. LL gave you a better chance to hit a window of opening for some rides. If they broke down every hour and the line is 1hour 5 minutes, you missed your shot. And yes they broke down that much. Yes I'm looking at you MMRR!
Also, when a ride breaks down and comes back up, they let a LOT of LL in first so the standby line sits stagnant. Imagine thinking how you could've paid that extra money while watching a marching bands worth of people stream in.
We got everyone magic bands (and magic band clip savers!) and our son had a blast clicking into the rides. He looked forward to it and would get his little wrist ready. Very fun. Expensive but a nice souvenir.
Enjoy your trip! Honestly, you're an amazing person to be helping everyone so much. When I think about winning the lottery, I think about doing what you're doing. Congrats on living my dream!
If you have any more questions feel free to PM me since my trip was so recent/mirrors yours.