J-10 just cannot reuse Lavi's aerodynamic data. Lavi has flaws in design on its canard and main wing combination. There is an article in Chinese discussing the issue,
http://dy.163.com/v2/article/detail/CU3AU8IF0515I1K0.html
In short, Lavi's pitch down control is terrible.
Look at the pictures in the article, you can see Lavi's design is very unique and somewhat gone extreme, while canard employed designs from other countries are all different to it.
Unless Israelis move the canards forward and change the main wings to delta wings, they just can't put that into final production.
Saying the Frenches sold their Rafale knowledge to the Chinese while they sold the FBW software would be a lot more credible.
BTW worth pointing out that JAS-39 is very similar to J-10 on canard and main wing combination.
If you read the article by Golan, you will see a detail Lavi was designed with higher lift thus it could out turn the F-16 at lower altitudes and speeds but it had lower thrust to weight ratio, so it accelerated poorly compared to F-16, and it turned poorly at higher speeds compared to F-16, why? the Lavi was not designed to intercept fast aircraft, and they chose a simple fixed ventral intake to reduce weight, so as an interceptor and air superiority was poorly suited, also on turn rate its lower TWR meant F-16 achieved higher STR specially at higher speeds.
the F-16 early configuration will lead you to see the F-16-Lavi-J-10 connection
J-10 is more suited as an interceptor, its profile is sleeker, and in the early version A it has a moveable intake ramp, when you look at J-10, it shares a common position for its ventral fins, coincidence? no it is not, Lavi tested a configuration of tail booms twin vertical fins of higher aerodynamic performance at high AoA than its single dorsal vertical fin and two ventral fins, but as on F-16, they went for single dorsal and twin ventral fins due to lower weight advantages, coincidence? no it is not coincidence because if you look at the wing position it follows the same solution and the single dorsal vertical fin and twin ventral fin reduce weight .
On the J-10, a two-dimensional variable intake air intake is used. Its shape changes due to two movable panels. This design meets the increased requirements for aircraft when conducting air combat. In addition, the use of a variable geometry air intake contributes to an increase in the dynamic pressure in the inlet device (by about 5% with M = 1.5, 15% with M = 1.8 and 25-30% with M = 2) . As a result, significantly improved engine thrust performance and its efficiency at supersonic speeds, which contributes to an increase in maximum speed and acceleration. The main disadvantages of using variable geometry air intake are the increased visibility of the aircraft when the radar is irradiated in the forward hemisphere, the size and weight of the structure increase, the attendant increase in the cost of the aircraft, and the need for additional maintenance of the air inlet control actuators
Look at the Eurofighter, Rafale or Gripen no ventral fins, this has to do with the position of the canard and intake type besides the size of the vertical fins, J-10 shares much more commonality with Lavi than with Eurofighter, its design of J-10 is an improved Lavi with a switch from ground attack role to interceptor/air superiority tasks.
Remember Israel had already F-16s and F-15s, so Lavi was designed as an aircraft it could dogfight if needed, but not as the main air superiority, F-16 went that way too albeit by powering it with higher thrust engines to allow to keep a similar TWR.