- here are some thoughts, though they may or may not apply to your situation. They are all things that I have gone through myself, so please understand they are not assumptions about your situation, but my hope to convey things that can happen with dormants in warmer zones.
I buy from big box stores whenever I find a good deal, too. Normally, any flower sold in a nursery, floral shop, or big box will have been "forced" into bloom and grown at peak-fertilizing rates so that they are big, blooming and ready to buy. That said, they often do quite well their first blooming summer, and then begin to dwindle back by the next. And, sometimes those store plants are from tissue culture, which some say may weaken the plant's long-term endurance overall. So, I have to take some extra steps to keep store-bought fans going until they are established. I give them more shade, less shelter in the winter, and do start trying to fertilize (Osmocote - its so easy and gentle to use) by the next spring.
According to the USDA site, based on your zip code you are actually in Zone 8b, which is very close in temp ranges to 9-10. They updated the zones a year or two ago and those of us in the warmer areas got bumped up into "higher" numbers. Since three of the four daylilies you listed are dormants, and one is semi-evergreen, it is possible you may experience what many of us in higher zones do ... dormants, and even semi-evergreens, can be a real struggle to keep going.
Also, my few dormants always die back in the winter, even as warm as it is in my zone. So, I have a whole section right now that appears to be "dead" with just one or two daylilies poking up the tiniest little tip of green (when I brush away the fall leaves to check). Last year I thought they were truly dead, but was surprised to see green popping up once it got over 50 degrees overnight. Unless you dig out the suspected "dead" daylilies, and find their roots have actually disintegrated away, they may still be in there. A case in point, I was sure my Frances Joiner (dormant) was dead at the end of November when I was finishing clean up in the garden. I was rearranging things so I thought I'd just dig up and remove any leftover FJ debris and keep the area for some annuals next summer - I left the area very rough, uneven, and untended. To my surprise, there is now the tip of a fan of FJ starting to emerge. No other fans were planted in that area, so I am sure it is FJ. I must have missed a crown when I tried to clean out the area, and for all appearances, it was a "dead zone."
So, even though some dormants may make it, at least for a year or two, I try really hard now only to buy evergreens (or the occassional semi or even dormant that I can't pass up) so that I can see, and enjoy, that wonderful evergreen foliage all year round. Lots less wondering about it or needing to replace, for me.