Yeah that'll work pressure treated is also fine and more rot resistant than regular wood 

Dogs leave hair behind, but (typically) don't damage anything **knocks on wood**.

Are you sure MDF because if so that is problem #1, everyone will carry and have wood, which is what a build-up trim needs to be, so it can be fastened properly. 

@Caleb Brown we put an offer in sight unseen with an inspection contingency for this very reason.

Just make sure you are not purchasing something sight unseen.

In the current climate with deals selling higher than they should and properties going sight unseen more than ever, an extra day to get your offer in can make all the difference. 

After removal of the drywall and floor coverings the wood structure and framing would be treated with a surface applied water-based encapsulating sealer to help prevent the release of any odors that have penetrated into the wood components.

Wholesalers are loving the emotional novice buying chasing winning a deal more than a deal that wins, flipping is much the same in focusing on perceptual value from pigs with lipstick and buyers so wrapped up in just getting something approved there loosing sight of what they are winning.  

To give some context, the house has rotting wood siding that’s about 40 years old.

Again, for an investment, I want to be sure i'm not walking into a money pit such as bad foundations, significant wood rot, a really failed septic, etc.Are you asking about a fixer-upper?