I do think the smoke on page 129 is foreshadowing! While it's likely that Minna didn't have all the details worked out yet, smoke is a pretty clear marker of disaster (or, it could be a signal, as we have discussed elsewhere).
But hey, we skipped over page 127 and Emil's hairstyling, which led to several people in the comments making extremely shippy comments, like "they are now a canon couple to me". (OTOH, I also see a lot of Emil & Tuuri shipping. Like on page 135.)
Regarding Emil's family's wealth, as displayed on pages 130+:
-- Siv says the house is the last nice thing they own, so she knows it's nice.
-- Torb tells the nanny 'we'll sell some things and pay you more', which somewhat contradicts Siv (they do have some other sellable things!) but is in character for both of them. It also clarifies how they've been paying for stuff: by selling off the remnants of their old lavish lifestyle.
-- But, yeah, the radio was probably a necessity. While staying on a base for the duration might not be so expensive, paying someone to watch the twins would be. Also, it leaves them free to give the crew instructions about secret book salvage. At a base, they could be overheard.
Page 133: being in school until 17, like Emil, is unusual! Also someone is sad that Emil is imaginary.
Page 135: commenters guessing that Lalli will one day surprise Emil with magic. Oh yes he will.
Page 136&9: Emil sure is suspicious that Torb is trying to rip him off, isn't he? I wonder if there's a story there. Also, regarding the books: I just had the thought that there should be copies of many possible books present in Iceland. Shouldn't there? Or did Icelanders eat/burn them during the first lean decades?
Page 138 - Sigrun in her first speaking role!
will continue later...