Are these spider eggs?
Yes, those are definitely eggs.  And I believe that is a female grass spider (Genus: Agelenopsis).

Eggs are typically laid in late summer or fall and spiderlings emerge
the following spring....A female that has mated with a male can produce more
than one egg sac. For some species,  it’s common to see two sacs at a
time, side by side, attached to a surface (such as the underside of a
rock, piece of wood in a wood pile, or in a rolled up leaf, for
example). Each different species of Agelenopsis may create a slightly
different egg sac, but typically each one contains anywhere from 50 to
200 individual eggs. The mother spider will remain near her eggs,
dutifully guarding them, until she dies around the onset of winter.

This seems to fit the picture to a T.  I'm not 100% about the species, but I believe it is either A. aperta or A. oregonensis.
Edit:
As user Xan pointed out, this could likely be a lynx spider (Genus: Oxyopes; likely species: Oxyopes salticus - female).  This would explain the defined setae (bristles) on the legs.  To really decide, you would need to check the following characteristics:

Eye pattern: Lynx spider eyes form an octoganal pattern, while grass spider eyes form two, parallel, curved rows.
Spinnerets: You would have to search for spinnerets on a lynx spider, while grass spiders have two very prominent hind spinnerets that you can visibly see from above.

I originally thought those were spinnerets in picture 3, but upon closer inspection it looks like one of the hind legs folded underneath.