Not really because not much value is yet being attributed to NC...

Not really because not much value is yet being attributed to NC within the PLL share price - Approval is just a heap of future upside.

I'd assume that most of SYA's market cap is due to having 75% of a soon to enter production asset. For simplicity let's assume non-NAL assets of SYA are worth $400m and SYA has a $1.9b market cap. This puts SYA's share of the NAL asset at $1.5b and the NAL project value at $2b. PLL's 25% share of this is $500m.

Ignoring any strategic value that may mean above market price for A11/SYA, PLL's ownership of shares in these companies is worth about A$250m (with a lot of upside potential).

Atlantic has a market cap of $400m and essentially all its value is half of Ewoyaa. PLL will have the other half so this is also worth $400m (again with lots of upside potential).

Tennessee Hydroxide is hard to value. There is already a US$141.7m grant towards its construction. The NPV was US$2.2b (A$3.1b) and that was using $22k/t for hydroxide. I'd suggest a slightly higher value is warranted which would increase the NPV. If you valued the project at 25% of NPV and added on the value of the grant then the value is about A$1,000m.

Lets add these $500 + $250 + $400 + $1,000 = A$2.150b

You might notice that five assets of PLL haven't been listed in this value:

1. Upside value from any Hydroxide/Carbonate plant at NAL
2. The value of the Spod off-take from NAL
3. The value of the proposed NC operation (which is modelled as a $2.8b NPV, EBITDA $592m/yr)
4. A first mover advantage as a listed American company in acquiring/investing in desirable future projects
5. A market price off-take to half of Ewyoaa product allowing source material for Hydroxide plans at Tennessee

I know you noted A$1.7b value, but with 1.8b shares on issue and a $1.035 share price PLL has a A$1.86b market value that needs to be justified. Either way, the A$2.1b above is still higher and that's before adding any upside from items 1-5 above. Some commentators have valued item #2 above at close to the current market cap of PLL.