I’m so sorry for all my questions on this part. I just found the whole thing really hard to follow. At the beginning it felt like Rina was jumping around all over the place - one minute talking to this person, the next apparently back at the house - which made it really confusing to me.
Page 181
これは、タマにサンデーのおもりをおしつけたリナにも責任がある。
This is Rina thinking in response to Shika’s revelation that Tama seems to have toothache.
I’m a bit confused about who is foisting babysitting of whom onto whom here
but I realise that Rina is realising she is somewhat responsible for this happening too.
Page 182
This is the part where it felt she she was flitting about all over the shop. Anyway.
リナが、「いいご主人ね。」というと、タマはほこらしげに、とららしく、ウオーと大きくほえた。
Is とららしく “like a tiger” / “appropriately for a tiger” etc? I found it a bit weird with とら in hiragana.
算数の問題からときにかかった。
What does this mean? I understand the words but not the sentence.
Page 185
もの音がするのでふりむくと、シッカにつれられてタマがはいってきた。
I don’t understand why it’s つれられて here rather than つれられた? Isn’t it a relative clause describing Tama as ‘brought along by Shika’?
Page 187
「なんてお礼をいったらいいかわからないくらいです。」
I think Monday is saying something like he doesn’t know what would be a good way of saying thank you to Rina, but then I don’t understand how the くらい fits in (or if I’m even right). This is after he invites her to eat with them in celebration because it’s all thanks to her.
Page 188
「例の虫歯はいたむやら、暑い日で、指にあせをかいて、オルゴールの細工はうまくいかない、妻やサンデーの声は神経にさわるといった調子で、かあっとしてしまいましてね。」
(Monday describing the fight)
I second Sylph’s query - is this talking about his “usual toothache”, and we are to understand that this is something that happens frequently because of his candy-munching habit?
Also, does it say at the end that he lets out a ‘caw’ sound? In frustration, I assume?
「妻にあたってしまったんですよ。」
Is this saying he confronted her? Oh wait, it’s intransitive - does she confront him, presumably to ask why he’s yelling?
(this was a rough page)
「わたしは、サンデー自身のために字をおぼえてもらいたくていっしょうけんめいだったのに。」
(Kinu speaking)
I’m confused by who is いっしょうけんめいing. Kinu wants Sunday to learn his letters for the sake of his own self-confidence, but then is it Kinu trying her hardest to teach him? So it’s like “even though I was just trying really hard to do something for the sake of our child, he called me an old hag”?
Page 189
「しかっても、おだててもだめだから、いまにとるだろうとほうっておいたら。。。」
(Monday talking)
Just don’t understand what いまにとるだろうとほうっておいたら means.
Page 190
お面さえしていなかったら、すぐキヌさんとサンデーが親子だとわかったものを。。。
I just don’t understand さえして? I realise it’s saying that now that he has taken off his mask she can see that they are parent and child, but for some reason I can’t work out the verb. My brain is a fog 
If anyone can help with any of them that would be awesome. There were quite a few more I worked out as I typed them up 