"I'm wondering if this is due to me not watering/the heat or if this is just the natural cycle."

A little of both :-) With the unusual heat we have had over the last 6 weeks or so, hydrangea flowers are just not lasting very long. And that's what they look like as the blooms go over.

As to the type of hydrangea, it is a bigleaf or Hydrangea macrophylla cultivar, commonly known as a 'mophead'. Identifying the specific cultivar is a bit trickier - there are 100's - but with that coloring, I'd guess it to be one of the more stable pink flowered ones, like Alpengluhen (or Glowing Embers) as PNW soils are acidic and blue is a more common coloration for most mops.

And yes, you can deadhead the spent flowers as you wish.

That is a healthy plant for this time of year. June and July are the "show period". August - October should be basic maintenance and prep for next year.