哉 (かな) 、「かなぁ」。

Have been looking through an Issa archive for summer haiku to learn to write in hiragana in 習字 and keep coming across, at the end of a poem, 哉 (かな/kana). Is it related to the wondering かな(ぁ)? Jisho has it as exclamatory—"what a...!" "how...!"—but also as "what" and "question mark". かなぁ in modern usage seems to be something like that, sometimes an interrogatory か + a wondering/internal なぁ. I don't know whether it's used outside of a sense of wondering.

古いかな。 furui ka na. I wonder if it's old.
悪く決まったかなぁ。 waruku kimatta ka naa. Maybe it was decided badly.

漢字の字源は何だろうかなぁ。 The parts are earth, mouth, and halberd. Jisho says it's archaic but still 人名用, jinmeiyou, pre-reform kanji still used in names.

Interestingly, it seems also to have the reading や ya. I wonder whether it was ever written as the "cutting particle" in haiku such as 木の陰や。 そんな説明は本当かなぁ。