I'm aphantasic, and I read that book during psychology studies. I actually used the method of loci for a social psychology exam where we got 320 total questions + answers and a random set of those questions would be on the exam. I used my parents farm as the location. It worked surprisingly well for me, considering I couldn't actually 'see' any of it, but rather used my inner spatial sense, combined with alliterations/rhymes for some connections, to form the memory.
I have very vague memories from childhood (and in general). It's all quite abstract, with the spatial sense substituting for real imagery, and perceiving 'silent' voices when recalling conversations. There's no smell, taste or physical sensation. If I remember an embarrassing situation, there is the an emotional component (cringe), but even the emotional component is usually quite weak
Daydreaming: Not in the way that I think people mean when they talk about daydreaming. I'll close my eyes and think sometimes. I usually get bored with that pretty quickly though, since it's just inner monologue/dialogue without any real sonic component