Answers

Yes. macOS shows one Dock icon per running process and every Chrome profile runs inside the same process, so Apple's Dock cannot do it.

On Windows, Chrome registers each profile as its own taskbar entry, so a pinned Chrome becomes the first profile you open and further profiles appear beside it. macOS has no equivalent, so the Dock shows one Chrome.

Out of the box you cannot: Command-Tab cycles apps and Command-Backtick cycles the windows of the front app only. To move through every open window with thumbnails, most recent first, install a switcher.

Not with Apple's Dock: macOS keeps a single Dock that jumps to whichever display you push the cursor into, and there is no setting for one per screen. Superdock can put a dock on every display at the same time, and can show on each dock only the apps that have windows on that screen.

Because the Tahoe Dock floats as a Liquid Glass panel and no longer claims a strip of the screen, so a window zoomed to full height now extends behind it. Apple offers no toggle.

Not by itself: hovering a Dock icon shows the app's name and nothing else. Two apps add Windows-style thumbnails.

Because Command-Tab activates an app, not a window, and macOS considers a minimized window to be parked in the Dock rather than part of the app's visible set. Holding Option while releasing Command restores one minimized window; a window switcher such as Superdock's lists every window, minimized ones included, so you pick the one you want.

For two windows, Command-Backtick. For more, or for windows spread across profiles, the fastest path is a Dock tile per profile: one click opens the right profile's windows, right-click lists only them, and Option-Tab shows every Chrome window with a thumbnail labelled by profile.

Not with Apple's Dock; the glass beside the last icon does nothing. Superdock gives each end of the dock an action you choose: Show Desktop, Mission Control, Stage Manager or nothing.

There is no single best; it depends on how much of Apple's Dock you want to keep. If you want Apple's Dock untouched plus hover previews, DockDoor.