Permitted 600sf garage enclosure with the City of Tempe.

Perhaps have a pet addendum that lays (no pun intended) out your criteria - ie:  they need to live in a fully fenced enclosure and they are not allowed in X areas.

Don't put the drain field or other parts of the system in a high traffic area including driveways (if it is just a pipe, I put them into a second protective enclosure like a culvert style pipe), under something you are going to build or livestock area.It is best to not have a disposal in your kitchen when you are on a septic.

I'm assuming your duplex doesn't have a pool so probably no pool cage (screened enclosure).

I can do this.......Two years later and I'm gutting the enclosure.

You could get one of those plastic shower enclosures.

The limb knocked out the bottom section of my patio enclosure screen door as well as some of the window screens. 

As far as a $1,000 budget, I would probably do a few things:1) design and buy a back window sticker for your car (or tailgate of your truck) so when you’re driving around folks will see what you do (very cheap and effective advertising).

The question remains tho, what will you find when tearing out the drywall - is there more damage behind the enclosure, are the studs behind the wall in bad shape?

You might want to do an enclosure around the trash container.