Im going with 14.0 - 15.9m.
My reasoning is I expect it to do slightly better than PS4 as PS4 and XBO are dying quicker than PS3 and 360.

I'm expecting about 16M due to PS4 sales breaking off and going to PS5/XS instead as a result.

I voted 10-11.9m. No way is PS5 selling better than PS4. I can't believe how many people actually think this will happen. Some things to consider:

1. $500 price tag
2. Looming recession
3. PS5 has much tougher competition than PS4 from both Nintendo and Microsoft.
4. Launch data is basically irrelevant. Even the Wii U sold well when it launched.

I expect for the first year of the PS5 to sell better than the PS4 due to very high hype at launch and demand right now with the lockdowns - but after that I expect the PS4 to lead and never look back.

Couldn't say. I think within a few months we'll have a better idea. When demand is outstripping supply, you don't know if it's just 5 million people who really want one, or 55 million. And whatever the x-factor is now could change substantially if PS5 fails to stir up excitement over the next few months. Japan was a disaster despite the highest supply in history.

Assuming that they'll be able to produce enough units to meet demand (which we know is not the case, because I cant go buy one at retail today), I'd figure on slightly more units than the PS4 sold in the first year. So, maybe 16mm or so. However, since they cant produce enough units, I'm thinking it'll end up right around the PS4's numbers. Of course, if supply troubles continue throughout the year, it'll be lower. They can't sell units that don't exist.

As to the bonus question.... I'm interested in Horizon and God of War. But, since I started this gen with XBox, it'll be a couple of years before I have a PS5 to play them on. So, I haven't been paying a whole lot of attention. There may be something else that I've missed.

I think somewhere around 16 million if the line-up is good (games like God of War, Horizon and even GT7 would help a lot) and if there's enough supply.

Bonus: Final Fantasy XVI (I think this will come out until 2022)

It had a record launch followed by serious shortages. They are sacrificing PS4 production and marketing and already sacrificed its Xmas 2020 to push its successor as fast as possible, moreover unofficial rumours say Sony is planning to produce 16-18M in 2021, anyhow for a first full year 18M would be really huge, actually the biggest first full calendar year ever for any console by quite a large margin, so I'd stay a little under that max unofficial prediction.
So, considering the little we can already know, I'd say 16-17.4M. Very optimistic, but considering Sony sacrificed the last possible big year of its current cash cow to make it happen, we can expect it to make all the efforts possible to achieve it.

Yeah I know. But with Nintendo and Sony systems, historically, Japanese pacing has always been extremely indicative of their ongoing success, and your chart also very distinctly shows the PS5 lead diminishing rapidly. At the pace things are going, when that chart is expanded to 9 weeks, PS4 will be ahead, and I foresee it staying that way.