Textbook Translation

いつも違う: always different
いつもと違う: different from usual(= unusual)

To use multiple は is not uncommon even in conversation. むかしは is the main topic of the whole paragraph following it, and the rest はs indicate the topics of each sentence.

"Clause/Phraseのは、～からだ" is a structure expresses reason. の is a nominalizer.

To conect clauses/phrases only with the -te form sounds childish. Also, single kana -masu stem such like 着 tends to be avoided when connecting clauses.

Thank you so much! It's all very clear. Helpful as always. I'll post more when I get to roadblocks.