IAI did have some involvement in early wind tunnel testing but it was a relatively small group of around 20 engineers. I suspect it was a consultant type role as they of course had recent experience with a close coupled delta Canard Configuration
From AWST November 1995
Both a Zhuk Radar and an Israeli EM-2035 were evaluated but the Chinese went with the domestic KLJ-3 which was an evolution of their experience with peace pearl.
The HUD MFD package seems to have come from IAI, the Chinese had not developed such a system at the time and were happy enough to use the Israeli avonics (some versions of the J-8 and J-7 will use various avionics from Britain, Israel and others).
AWST March 1995
They ended up using a domestic radar and a domestic RWR (I think a version of what’s on the PAF J-7). Looking at the hud and MFD from Chile’s F-5 III though I seem a bit of resemblance.
The Lavi and J-10 don’t share any lines so I imagine it was more general experience. The early J-10 was also an all metal aircraft structurally more similar to the mirage then Lavi. The later J-10B/C have much more advanced composite construction but those are almost 15 years after China and IAI stopped working together.