Entire episode felt nostalgic of being sick
. I get dream hallucinations when I'm running high fevers and I can definitely empathize with what Ohana was probably feeling.
While I wouldn't take the dream sequences too literally, it does seem like there was some significance with Kou-chan (who knows maybe Hanasaku is about to turn supernatural on us, lol), although only time will tell if it can be directly interpreted as "Ohana choosing Kissuiso over Kou".
An interesting tidbit of dream analysis. It really depends on the individual, but it is possible that Kou is not intended to be a literal representation. Perhaps Ohana's subconscious fears of inadequacies manifested itself as Kou because it is something she is familiar with. Kou represents everything she left behind and which is still a relative "safe haven" for her to escape to if things fail at Kissuiso. This dream may only represent her feelings of solidarity at Kissuiso. It could be a bit of foreshadowing by the author, but it'll take more than this to convince me that Kou is definitely out of the picture. Also the interesting cameo by what appears to be a miko loli and a fox could be a reference to Inari's domain and the warding against of evil spirits or influences (Ohana's fears of inadequacy?).
On a side note: Tohru has officially become a legitimate rival to Kou!