"Fingers crossed"

And about David Greene being wrong....

I am still green and am having a hard time visualizing that deal.

@Tyson Cross Wear that MH Park stigma with pride! 

Your original plan of moving the toilet up on the other side of the wall on one side to make it cross a joist to get to the stack...Alan, if you try this, tapping a 3 1/2 in. hole in what I think is just a 2x8 joist to get the plumbing through, or doing some kind of wild drop arrangement below to get it past that joist, that's really not going to work out well long-term.I would LOVE to hear the bid you get from the plumber to do this, though.I would also like to add emphasis to something about DIY that @Steve Vaughan pointed out, with its many echoes from my teaching days.

They cross many platforms.

When the cat is outside it may be no ones responsibility.Your solution to keeping your indoor cat calm and your children relaxed and happy might be to use one of the "Cat Boundary Sprays" you can buy online or in a pet store.Try spraying it on the window ledge inside and outside (it needs to be reapplied every so often) and some cats can "Hold Their Breath" and cross it, but not sit their while they smell it.It's cat repellent that when it dries they don't like the smell, though you probably won't be able to smell it.Spraying it AT THE CAT doesn't work, it only wastes it, it needs to be sprayed on an area you want them to avoid and then it needs to dry (it's not bug spray, it's a stink that cats want to avoid).Also here is a link to The Feliway Cat Comfort plug in diffuser, it helps keep indoor cats calm and happy (its a love phermone that only cats can smell) https://www.feliway.com/us/Products/FELIWAY-CLASSIC-DiffuserGood Luck!

I bet David Greene's book on BRRR is good, too.

Look for obvious signs like water leaching out or very green or higher grass.

As for some tips and tricks I would check out David Green's podcast on BRRRR and Alex Felice talks about delayed financing which only takes 8 weeks, both are explained really well!