Sorry, just as you realized, Chikara (and Yvonne) cannot be romanced! I am considering spin offs for them (no yuri though), but I won't actually say anything until I can finish this game first.
Also, if you think the cashier is hot already, I'm sure you'll like her even more in casual clothes lol
As for the backgrounds unfortunately my BG artist, z.rose, couldn't finish all of them in time, so I had to use some free assets (no stock pictures though, you can find the artists' names in the credits) for the rest. But they haven't stopped working, so I'll replace the assets with original backgrounds in a later update! They made the animal shelter and Hannah's room ^^
Story-wise, you're not the first one to tell me that and I've taken note for the future to hopefully not make the same mistake. Creating a nice pace is harder than I thought.
Finally, thank you so much for reporting this bug! I'll fix it immediately and upload a new build asap.
That said, thank you very much for writing your honest thoughts and I can't tell you how happy I am you like Chikara! She's always had a special place in my heart <3