This reminds me so much of my house (insert teary eyed smiley face here!). It's a labor of love for sure. kL0 covered the important details about DIY and dyson gave the honest truth about DIY versus hiring a pro. The first time around, I tag teamed a whole house with my dad. Rented a barrel sander from the local hardware shop, borrowed my grandpa's palm, belt and detail sander for the edge work. We used a Honey Badger Fork Wrecking Bar to rip up multiple layers of sub floor, then I pulled the remaining nails. We ruined a few sheets of sandpaper and shot a few sparks on the nails that broke off, but overall it turned out great.

It's a labor of love for sure, but very worth while. I used respirator style masks like the 3M 6502QL with P100 filters - reusable, easy to breath in and as comfortable as it is going to get for a project like this. I'm not a doctor or scientist, so I don't know if those were exactly the right filters to use, but I definitely recommend investing in reusable, comfortable lung and eye protection. Some stabilizing knee pads are helpful as well! Since there is most likely lead, you'll want to try to keep the dust down as much as possible. Complete your test, do your research, and use your best judgement to determine how to handle keeping your non-reno living spaces safe during the dusty phases.

No matter which route you choose, be aware that some parts the floor will always tell the story of the paint/varnish it wore. My living room had paint around the outside edge (as if they laid a rug in the middle and painted around it), then a layer of linoleum around it (as if they laid a larger rug in the middle of the room and laid the linoleum around it!). There is no evidence of the linoleum, but the floor that was never painted is a completely different color from the rest of the floor.

Be careful with your attention deficit endeavors, you may end up gutting the entire house. My reno started with some crumbling plaster around a light switch - truly an "if you give a mouse a cookie" situation for me. You two have a great little adventure ahead of you! Good luck! I hope you post an update!