Shelly Dimmer 2 - L inputs wiring

I want to use Cross-Connect with N wire case. (ShellySupport Wiring)

BUT, comparing with user manual wiring scheme Fig 1 (UserManual Wiring) I have 3 questions:

1. Can I connect switches directly to main L line, like ShellySupport case? (Is it not mandatory to connect switches L line to shelly L terminal?)
2. There are 3 L line inputs at Shelly Dimmer2. Can I use any of them to connect L line main power, like ShellySuppor case? Or I have to use specifically central L input one, like User Manual?
3. 3x dimmer2 L inputs are internally connected together?

Thank you,

Arnau

Thank you for fast and clear answer thgoebel.

See you inside forum.

BR,

Arnau