In what direction does that hill point? I ask because that looks parched, not dying (or, dormant, which given the weather for the last two weeks is not surprising in the slightest). My mother's southern-facing hill looks very similar right now, and my slightly tilted southwestern face is nothing to write home about right now! Dormant grasses will pull easily, but avoid doing so as it damages the remaining crown and roots. If it's dormant, it'll return with adequate water. Which means it might start this week as we're due for some unstable weather patterns.

xdriver, I had the same issue as you (at least based on the pictures and description). Spent a lot of time and money to make sure my overseeding was going to be as successful as possible. Grass came up perfect and then mother nature wouldn't let the sun come out for over a week. The non-stop rain day and night for a week is what I believe to have caused my Pythium (along with my excessive seed rate in certain spots). Since I was not able to get Heritage (due to several factors)I took timeco's advice that he gave me in a thread I posted a couple weeks ago. As soon as I saw no rain in the forecast for at least half a day I sprayed Immunox (found at HD). This seemed to stop and confine the spread to the few areas and now that the sun is back I hope that will be the last of it for this year. Since it is getting a little late for seeding now I think I will just try to dormant seed my bare spots this winter since they are not that large and that way hopefully by spring my lawn will be back to normal. Also search cornmeal here in GW. Although I have no personal experience, based on peoples positive feedback it seems it may be the cheapest and most effective way to avoid the common lawn fungi (applied about every ~30 days). I plan on giving this a shot next year. Good Luck!

If it get's "very little sunlight," it won't survive where you have it anyway. Didn't the "directions" say it needs full sun? Chances are, it's suffering from not being watered while you were away. Newly planted grasses need to be watered every day at least. If you live where the current heat spell is happening, it's even more important. Water it 2-3 times a day until the heat subsides. Then move it to a sunnier spot, and cross your fingers.

The grass is dry. That can happen from not enough moisture or from rotten roots not letting the water up. Are you getting puddles of water in the dry areas? Puddles can allow fungal rot to set in. If no puddles then the areas are not getting enough water. That could be due to sprinklers not adjusted right, runoff from hydrophobic soils, sandy soils allowing moisture to run through, or simply the idea that you need more than 1 inch per week this time of year. My guess is your sprinklers are not adjusted right. That's more of an educated guess because I can see what appears to be a circular shape on the grass in your big picture. Mid way up from center to the right side of the picture is a nice colored circle(ish) green. Outside of that is the dry area. If you put cat food cans perpendicular to the circle and turn on the sprinklers, you will probably see that the cans are not filling evenly.