You're on point with everything you said RAW, however.... you didn't take what Malicious wrote about his pt composition and level.
All that I wrote is valid if you take into consideration his units: lando, phasma, qgj, gs and sth - undeargeared, underleveled, understarred. Idk about mods.
STH is not useless. He starts with his taunt = turnmeter for all others and Biggs+Wedge+ (a third) oneshot that QGJ before he has even started his first turn.
Although right on spot, totally irrelevant to Malicious team compo. ALso - with his not-yet-6* STH I doubt he has such good mods to go first. Not to mention lack of wedge and biggs. If it comes to overall situation I even run sth against Baze which can't be done in first turn and has 2 taunts. Just being smart can make each unit viable in arena :)
STH (not wedge), Biggs, Lando, Boba, GS.
Boba makes a big difference. His team is much weaker than yours.
Malicious - I would still follow what I wrote, unless you do get some better mods, units and gear. My answers will be irrelevant if you progress. Just adjust as you see fit.
You mentioned in your top10 fleet arena people are no whales, however in mine there are.
Yeah, I'm lucky on that part since I don't have them yet at the top, but they will come. I barely started fleet arena and they will crawl up to top10 eventually.
Also in my Squad Arena there a some people who are far over lvl70 and can farm Wedge already in cantina battles since a few days, I still can't.
I wrote several times that my top1 in arena is way over 70 and rest is max 64lvl :) When I'll be 66lvl like you are now I'll probably have the same issue with multiple 70+ opponents. Wedge's are in every arena, in mine as well, even now. But not many.