As a very quick and brief explanation of the mains points:
CWMP is Customer Premises Equipment (or CPE) WAN Management Protocol, (also known as TR069). Basically, BT checking if any adjustments are needed to keep the line stable, any updates are needed, whether a 14-day reboot is due etc. Happens once every 24 hours by default, although I have two SH2’s and one of them seems to like doing it every hour for some reason. It does not provide access to your network and the Smart Hub is BT’s property, so why shouldn’t they manage it?
SIP (or Session Initiation Protocol) is the protocol that manages Digital Voice. Your phone number is now tied to your IP address. IP addresses are not permanent, of course, so every 30 minutes the SIP protocol confirms that the relationship between the IP address and the phone number is still valid and re-registers it. (30 mins is the protocol default. If memory serves BT’s implementation checks every 40 minutes).
Neighbour solicit is an aspect of how IPv6 works. Computers inside the network talk to each other via the MAC address (Media Access Control address). Your computer keeps a record of how the MAC addresses relates to the IP addresses and what the MAC addresses of its neighbours are. Periodically it sends out Neighbour Solicit messages asking its neighbours to confirm if they are still there so it can update its records. ARP (Address Resolution Protocol) is similar but the old and less efficient IPv4 way of doing it. Both are routine internal network housekeeping traffic.
The Port Scanning/Dos Spoofing is actually bad guys trying their hand but the good news is that the fact that it appears in the log means your firewall has seen it and blocked it. The IP addresses in those are fake (spoofed) and will appear to originate from all over the place. Sadly, it’s quite normal today and everyone gets a load of them.
In some respects, part of the problem is that the Smart Hub logs are too detailed and so look a bit scary. Most of it is just routine housekeeping though. All of this is available on Google, (and in a lot more detail than I’ve gone into here), so you can check for yourself.
I'm off to bed. Goodnight.