Dude - here's the thing ...
LCA Tejas Mk-2, "mutirole" version, or whatever you call it, would cost ~$30 -35 million each, half the cost of the super MKI and 1/3rd the cost of FGFA. Also, it will be produced in India, with >80% Indian components and a production line independant of foreign supply lines. Which means in wartime, India can afford to lose a hundred of the Tejas in combat and replace them by ramping up production. THAT is the main advantage of the Tejas Mk-2.
In a post 2020 airforce doctrine, India will have a top tier of FGFA/ MKI (~270, where older MKIs are gradually replaced by FGFA from 2025), a middle tier of MMRCA (~200, to be gradually replaced by AMCA from 2030) and a bottom tier of ~300 LCA Mk-2 (presumably to be replaced by some 6th gen combat drone from 2030).
The first order of 120 LCAs is just a beginning - like India's initial order of 140 MKIs from Russia in 2000. This was updated to ~200 by 2005 and then to ~270 by 2009.
As IAF becomes more accustomed to the aircraft and confident in using it, they will ask for more role changes and upgrades and in return will order more of the platform.
That has been the history of IAF with Mig-29s, Mirages, Jaguars, MKIs, and that is how the LCA is being treated. The same is the plan for the MMRCA winner too.