Dogsitting for 3 dogs–management suggestions help

Hi. I am dogsitting next week for 3 dogs (1 is mine and I won't be talking about him too much) 2 of the dogs have a very different schedule than the one I'm going to have to use with them and I'm trying to think of ideas on how to handle them.

My parents (the owner/caretaker of the 2 dogs) are both retired and home about 95% of the day engaging with the dogs. One is 5 year old Corgi, who will settle nicely but has major resource guarding issues (I do have management solutions for this and have watched him before), and is prone to weight gain so on a very strict diet. The other is a 1.5 year old mixed breed large dog (German Shepard, Lab, Pitbull and boxer mix) who has no ability to settle and my parents created a marathon dog with…he is not crate trained and the one I am the most worried about.

I do work 100% remote and have a great deal of flexibility in my work but I do need to be available for meetings and such.

The dogs normal routine is, wake up, go outside to go to the bathroom, eat breakfast, play outside for like an hour (with my dad normally) nap for 2 hours while my dad goes to the gym. Go on a 2 hour + hike, then they come home for another 2 hour nap, then the puppy goes to the dog park for like 2 more hours. Then more outside time (normally fetch), dinner, more outside playtime and then they sleep.

I cannot do this schedule and work. I honestly don't think its a healthy schedule in general for a dog this young, but it's not my dog and my parents have made it clear that they don't care about my opinion here.

My plan is, keep their morning routine very much the same, then for the first walk, give them some each some sort of food puzzle with half their breakfast. I will put the corgi into his crate for this to manage the resource guarding (and likely my dog too cause he has food allergies). Then after I get through work I will take them on a long walk (probably not 2 hours but a decently long walk)…they are all except the puppy good on the leash, instead of the dog park because I have no interest in dog parks. Then they get outside time, dinner, probably split in two again with half in a puzzle feeder for each dog separately, then outside. Then I will also do some brain game training with all 3. My dog won't go to sleep unless we do like 15 minutes of training every night so I'll just work with the other 2…

For the puppy's extra energy cause I know he will have some I am going to bring a flirt pole which he does like, and he does play nicely with my dog which I hope he will do to burn off some energy.

Thoughts on this? Any other sorts of recommendations you can think of? I'm kinda at a loss for other ideas as to how to handle a 75lb barely trained puppy who has no real off switch…I would love to do some settle work with him but I just don't know if it's too late (and I am almost positive my parents will just undo whatever I do when they get back…cause they think its normal to have a dog that only sleeps like 6 hours a day–yes he is 1.5 years old and doesn't sleep through the night).