Honestly I still don't know how far the NDA is lifted now, given how the book itself only is out to those who bought it at GenCon, so I definitely won't throw in rule-quotes with page references yet but I can answer some stuff. (To be honest, I don't really feel like it because some of these questions sound extremely leading.)
First of all: Thanks

> role of Strength for melee characters?
It's used in your Unarmed Attack Rating and Unarmed damage. Features in grappling. Plays a role in Athletics sometimes. Threshold for the Edge action Wrest, which is a cheap Edge action you can take after succesfully Blocking a melee attack. You also use a Strength test when using for example an axe to try to cut through a wall, to increase the DV for comparison. And of course you use Strength in several resist-restraining spells/powers. Bows need Strength for their Rating, which determines their DV. Medium Machine Guns need 2+ Strength, Heavy 5+.
(Also: Lifting now is S*S*10, so high-Strength characters are now much better at lifting stuff.)
And yes, if your Unarmed Combat Damage is heavy, e.g. 8 for an X(11) bone-augmented Troll, then using any sort of weapon will mean you do less damage. Because even the Panther XXL only does 7P base.
Not too bad, apart from the last paragraph. The fact that unarmed melee can stack so high is one thing (after all, that DS doesnīt necessarily reflect the damage of a single punch. And also, HULK SMASH!), but the fact that it makes armed melee pointless for high-strenght characters is something that should be looked into - if not by some kind of hotfix, then at least in the Combat supplement.
(I
may already have a kind of a measured houserule for this. Iīll see if its viable when I have a look at the full ruleset...)
> role of armour
Armor has a Defense Boost and Capacity for mods. Hardened Armor gives autohits equal to its rating, which is being discussed regarding game balance but fell outside of the scope of Hotfix errata.
I suspect that Hardened Armor = Spirit and Dragonscale armor (at least for now)?
Yeah that should definitely be discussed then. I just hope that discussion is about on
how to fix this and not about the question if its balanced in the first place

Iīd say just add the rating to the soak roll, like old-school armor in the previous Editions. With the overall lowered damage codes, that should already be worth a lot. Or itīs just half the rating in Autohits, like in 5th Edition. But the
full value in Autohits? O. Boi.
> Edge earned per round/turn/action limit stuff
- You can earn 2 Edge max per Round
- You can spend Edge once per Action
- When spending Edge, you can use a boost multiple times, e.g. spend 3 Edge to reroll 3 of your opponent's dice
I think Iīve already voiced my oppinion on the 2-Edge-per-round limit more than enough. It remains to be seen how often this limit applies in a real session, though. For the record:
If When I try SR6 for the first time, I will houserules this right away; but Iīll keep track on how much Edge
would have gone to waste if I actually applied this limit

Thanks for the errata and clarification on the other stuff. An RAI limit on Edge
uses per round would have been just as bad the
gain limit.
> action economy
Drugs, spells, adept powers, augmentations all still exist. HotSim got nerfed to 3d6 Initiative, meaning Matrix people face a tough choice between 2 Majors and 1 Major with 4 Minors.
There are a lot of Minor Actions. Plenty of useful ones. As to what you consider useful, I have no idea. Some people will complain, others will love the toybox.
This one sounds
really good to me so far. I can understand when some people miss the multiple passes from SR4 and SR5, but for me as a >90% GM, it was just too cumbersome hard to keep everyone engaged when the Initiative-Monsters played out their 1-2 additional turns.
> NPCs and Edge
They earn it the same way anyone else does. An entire set of Enemies may spend Edge only once per turn. So if you face 8 gangbangers and they split into 2 groups of 4 when attacking you, these two groups combined can spend Edge exactly once per turn.
The initial Edge value equals the Professional Rating, which ranges from 0 to 10. If you have a Prime Runner, they are like players so with individual Edge stats and gain individually as well. On top of that, a Prime Runner can freely steal Edge from his Professional Rating Grunt minions.
Wait, there is
still a limit on Edge uses per round, but for a whole group of Grunts? Or am just falling victim to the olī
turn VS
round confusion myself now?

So how does the Edge
gain limit work for grunts? Is there one?
> number of skills?
19. And plenty of skills you'll never touch, of course.
Magic: Astral, Conjuring, Enchanting, Sorcery
Matrix: Cracking, Electronics, Tasking
Specialist: Biotech, Engineering, Outdoors
Social: Con, Influence
Combat: Athletics, Close Combat, Firearms, Exotic Weapons
Other: Perception, Piloting, Stealth
I wonder where Intimidation is housed now? Influence?
> chargen metahuman builds
You can put SAPs into the Special Attributes and into your Racial Attributes, aka the Attributes where your Race has a maximum above 6. So Dwarf Body/Strength/Willpower, Elf Agility/Charisma, Ork/Troll Body/Strength.
> chargen priority E to Attributes
"Trap" is a leading phrase. Posts were VERY clear about it: There's builds possible with it that some people may consider viable. Personal preferences heavily apply. As for baseline human stat: That is not named. But only at PR 3+ do you get above average 2.125, Thugs-Gangers are all average 1.875-2.125, so pretty much 2 as baseline.
It remains to be seen what can build using the Attr. A or B can be viable.
But if it really turns out to be a "trap": Well... Donīt fall in it, I guess?

> lethality, relative and absolute
Leading question. A Troll can at max reach Panther damage. As for one-shot-kills: I'm not pulling out statistics when everyone can run math. If you want super-lethality, play with "Here comes the Reaper" rules.
One of my biggest concerns with the lethality is the viability of quick takedowns, which are important for stealth missions. If its next to impossible in to silently take a guard out with one (or max. two) attacks, mirrorshade espionage missions will have a hard standing without houserules or GM handwaving.
The Errata sheets mentions a Knockout Blow Action as an Edge use. I presume that this is already meant as one answer to this problem?
> is vehicle damage/repair still very expensive?
No costs are described, so up to the GM what the "needed parts" will cost you. It's simply a really lengthy process if the damage is massive: Damage-type modifies the interval, NOT the threshold.
> grenades/explosive - anything to mitigate what looks like very high lethality?
Don't run around like crazy so you can still run around, or simply involve any kind of tactical moves that will prevent you from being torn apart by grenades.
Silly silly Grenades. Itīs a tough thing. With a realistic DS, they are too strong and with a more balanced DS, they are not realistic.
I donīt know how armor comes into play when defending against grenades. I guess you still soak the blast with body only? Maybe thatīs a good start for troubleshooting once the laments about the new explosive meta start to swell: Just add the armor score to the soak roll against explosives. It would make a lot of sense: With the new 6th Edition armor mechanic alone, armor will likely contribute
even less to your survivability against explosions and shrapnell than it would against conventional attacks. In reality, itīs the other way around (at least to my humble knowledge).