I'd say, I think in Japan, "Yuri" relationships are well accepted, and I think any GAY relationships are well received, when it comes to partnership, Japan has a very long history of even registering official partnership of same sex relationships. So that part doesn't even concern me, their view on friendship, and closeness is different than most of the world and they are quite open for it too, as long as you don't bother others with it.
As for Kobayashi being attractive, well yeah she is the plain type, flat, outright washing board type of a girl or should we say woman, I'm not sure how old she is but I think she's well around 25-26.
Her interactions with dragons might seem odd, she simply accepts them as living, thinking and feeling beings, that are obviously superior in many ways. She acts towards them openly but politely in most of the situations. In Louca's case she became friendly with her enough to make remarks (and some insulting ones about their breast size difference) but she's still polite, especially towards Fafnir, about whom we know less and less for every time we see him, but that simply means that guy is simply adapting and changing.
Kanna is, on the other hand, a very young dragon, whose human form looks like a kindergarten kid, Kobayashi's interactions with her as we know, were not warm at first, but when they learned more about each other they became a family (along with Tohru) and seem rather happy.
Tohru is a difficult character, not due to her personality, but due to her upbringing, her past, and her wounds. She doesn't hate humans, even in her world, but she doesn't like them in her world, probably because they keep hunting her. Every time Tohru reminisces about something from her past life, Kobayashi simply doesn't pry, it's normal in Japan to not pry, if someone will want to speak about their past, they will say it, best not to push things, that's a mentality in Japan, one which usually helps but as everywhere, sometimes fails.
Tohru is obviously in love with Kobayashi for a few reasons, and for Tohru, they are all important ones.
It's very hard not to like any of the characters because they are all very well designed and developed over time.
Next ep is supposedly going to introduce a new character, I'm hoping it's that dragon girl form the OP/ED. It was hinted at her several times over the series but a brief introduction happened in this week's episode, next ep she's supposed to pop out and be angry.