'Chapter' two of Isomer is divided into three Paths, labeled A, B, and C. The A Path is the top of the side-scrolling layout. B is the central line, and C is the bottom. Route A has 2 Combat Stages, Route B has 3 and Route C has a single combat stage.
Chapter 2 sees a decent bump in difficulty on Normal, and by the end, your Echelons should be approaching level 70 4x linked.
EX is oddly easier in Chapter 2 than Chapter 1, with more forgiving enemy compositions, and the appearance of ELIDs reducing the threat level of the average enemy a fair bit. Don't get complacent though, most enemies can still ruin your day if you aren't careful.
The following teams are EXAMPLES only. They should be taken only as guidelines, not as hard and past rules for what you should use to complete these stages. Use your best equips possible in all cases. As a rule, aim for greater synergy than I have on some of these teams and please don't normally use M16 as a DPS. I do weird things for guide making purposes.
Normal Maps will need at least level 30 3x linked Dolls by the end, although at the start you can make do with weaker Echelons.
EX Mode does not play around. You will need to bring at level 90 5x Linked Echelons with good equipment, the best fairies you have (fairy requirements aren't that high, as you can see), and you will want a level 60 BGM (additional HOCs optional). The requirements for EX are the same across all chapters.