The problem with translating boke and tsukkomi as "funny man" and "straight man" is that it's mostly incorrect. It's just correct enough to fool people, but wrong enough to be wrong.
"Straight man" and "funny man" in Western parlance are about delivery. The straight man is always serious and composed, the funny man is hot-headed, emotional, or silly, or angry. As an example, look at Abbott and Costello (of "Who's On First" fame). Joe Abbott is the straight man, Costello is the funny man. Nobody could possibly argue against this and be taken seriously. We can move on.
"Boke" and "tsukkomi" are about who's the dumbass (boke), and who is correcting (tsukkomi) the dumbass. Watch Gintama. It's a world full of very stupid people doing nonsensical things with a perfectly straight face. Shinpachi is the only one who sees the absurdity and frequently reacts to it by going absolutely apeshit. He's the classic "tsukkomi". But he's also not a straight man. Straight men don't go apeshit.
It's completely possible for the straight man to be the boke, and the funny man to be the tsukkomi.
In fact, this is expected!
The premise of the very chapter we're commenting on relies on the implicit understanding that, in a comedy routine, bokes should act completely serious, and the tsukkomi should be loudly and violently reprimanding them for their stupidity. Elel herself understands this, probably because of all the variety TV she watches, and her failing was that she was so much a shut-in she did all her tsukkomi in her own head, not that she didn't realize how manzai comedy was supposed to work.