Yes. You can use general programming language and operating system features, such as initiating TCP and UDP connections. Through relevant language libraries, you can also perform operations such as connecting to databases and accessing APIs.
You can deploy a function to a VPC through which SCF can access resources in the private network.
There are several ways for a VPC to access the public network. For more information, see the NAT Gateway documentation.
It is random by default. You can also set a fixed public IP. For more information, please see Fixed Public Outbound IP.