Box 1: Yes. All traffic is allowed out to the Internet so you can ping the public IP.
NSG1, NSG2, NSG3, and NSG4 have the outbound security rules shown in the following table.
Box 2: Yes. VM3 is on Subnet12. There is no NSG attached to Subnet12 so the traffic will be allowed by default.
Box 3: No (because VM5 is in a separate VNet).
Note: Sub2 contains the virtual machines shown in the following table.
