Bar Height vs. Dining Height
The swivel bar stool pair publishes a 25.6 in seat height, sized for a 36-42 in island per its own listing; the 3-piece HDPE bar set publishes 28 in - the two are not interchangeable at the same counter, and neither is stated as a dining chair height.
Two bar products, two different heights
The swivel bar stool set of 2 states a 25.6 in seat height, sized by its own listing for a 36-42 in island. The 3-piece HDPE bar set states a 28 in seat height instead. These are published figures on two separate listings, not a matched pair - mixing the two at one counter isn't confirmed to seat evenly.
Where dining height fits in
None of the 8 dining sets in this range states a seat height for its own chairs, so this site can't state a specific dining-chair figure to compare against - only that bar height, in general use, sits well above a standard dining chair, which is why bar stools exist as their own category rather than a taller dining chair.
Checking before you buy
The number that actually matters is the counter or table height already in place, not a generic "bar height" label - measure it, then check it against the 25.6 in or 28 in seat height above (and the 36-42 in island range the swivel stools are sized for) before ordering either bar product.
Questions
Are the two Sunshine Valley bar products the same seat height?
No - 25.6 in for the swivel bar stool set of 2, 28 in for the 3-piece HDPE bar set. Not interchangeable at the same counter without checking your own space.
What counter height are the swivel bar stools sized for?
36-42 in, per the manufacturer's own listing.
Does this site publish a seat height for the dining chairs?
No - none of the 8 dining sets in this range states a seat height for its own chairs.