The whole phrase in the context of describing both 一夫 and 吾朗, in a literal way, means: "He (一夫) can appear absent-minded and you can't tell what he's thinking, so there are times when he can be percieved as off-putting"
I'll break it down, but first:
1 - Yes, that ようにも is like a regular ように、but it also has the meaning of addition from the も - you are adding up descriptions that fit 一夫. (the narrator is saying that on top of him being a "dreamer type", he's ぼんやり, and you can't tell what he's thinking)
2 - 一夫 is the subject, yes. You can re-arrange the sentence as 一夫はぼんやりのように見える (this sentence alone sounds a bit weird, preferrably you'd preface it with a word implying that it's a frequent thing or not, such as 普通に)
3 - Technically, no, the subject is an undetermined and tacit plural "you". Omitting such pronoun is standard practice in Japanese. 和子 is just the point of view character. (although not the narrator)
For the breaking down of the sentence, both the first and second clauses ("ぼんやりのようにも見えるし" and "なにを考えているかわからない") are connected by the ようにも you asked about and the しparticle, which is used to link clauses. Both are also descriptions of 一夫, since the last sentence's subject was also 一夫(and they fit the idea of a person that's a 夢想家 type.) The
third clause (きみ悪さが感じられるときもある) can be hard to link to the first two, but with this context, it becomes clear that those traits of 一夫can make him look a bit 気味悪い sometimes.