Solid Hardwood, Engineered and Laminate Flooring - Hardwood Floor Refinishing?

I have just removed my carpet from several rooms in the house to reveal my original oak hardwood from from 1947. For the most part in very good condition. There are some pet stains, as well as some gaps where the end of the boards meet, as well as some between the length of the boards.

I've had several refishing companies come out. They think the floor will come out fine, they've suggested the following and am wondering how this will all work out.

1.) Some days before they arrive where pet stains are worst, slightly sand to break surface and puddle with bleach.

2.) They will filly gaps/holes with putty. Will expanision pop this out?

3.) Will use 2 coats of Aluminum Oxide. Will this impart the wet look at does poly or do I need to stain to bring out the grain before the Aluminum Oxide?

Thanks

Hmmmm, no replies. here goes.
1. probably not a bad idea.
2. Depends on how wide the gaps are. This time of year everything is dried out and the gaps are wide. In August there may be no gaps.
3. confusing.....aluminum oxide is not a finish, it is the grit on sandpaper. Stain is a personal preference, but must be done after sanding and before any poly. If staining, extra care must be taken in the final sanding or every sanding mark will show in the stain. The level of gloss is determined by the type finish, satin, semigloss, gloss. Water based polys do not change the wood color, oil based polys give the wood a slight yellow tinge and will darken the wood.