IPv6 Lab: ISP & Client Side using Linux and Cisco

So I got really tired of reading about some basic IPv6  stuff and then forgetting it in a couple of months due to lack of practice and decided to set up a lab, which will contain both ISP and client sides.
This is what my topology will look like:

Components used:

• Client_PC: Linux box with Ubuntu Server 18.04 installed with rdnssd (which is required to receive list of DNS servers via RA);
• Home_Router: Linux box with Ubuntu Server 18.04 installed with wide-dhcpv6-client and radvd. (I had to install wide-dhcpv6-client, cause isc-dhcp-client, which comes by default, barely has any decent documentation and I wasn't even able to find out if it supports some of the features we're going to use in this lab);
• ISP_R1: Cisco C7200 15.2(4)S6. It's used as DHCPv6 server as well.

How I'm going to assign IPv6 addresses to devices (I'll cover the details of different ways to achieve this further)

• Client_PC: no DHCPv6 at all, only Stateless Address Autoconfiguration
• Home_Router: DHCPv6.

IPv6 Free Core: Configuring IPv6 Labeled Unicast on Juniper MX

Here's just a short note on IPv6 Labeled Unicast - an elegant solution to the case where you need to connect two IPv6 sites through your IPv4-only network. (The other option would, of course, be to enable IPv6 on all of your core routers, which is not always convenient).

So here I'm going to show you the minimal configuration to get this lab up and running, a trick that would make the configuration more optimal and elegant (why would you need "explicit-null"?), and take a quick look on what's going on behind the scene.

That's what my topology looks like: