Looks like the US is nervous about the guidelines released yesterday,which seem to be tailored towards the Rafale
India already decided for the Rafale in the MMRCA program. The Rafale offering has not changed dramatically since MMRCA, where the Rafale was too expensive.
If that would be the primary option, they would just revive the negotiations with France.
Eurofighter is even more expensive...
The infamous poor service provided by Russia makes the MiG-35 unlikely.
Boeing and LM are prepared to allow assembly of Hornets and F-16 but they do not control engine, radar, and a lot of the electronics inside, and Raytheon, Grumman etc are not likely to give away their company secrets. There are more than a dozen countries which have contractual rights to deliver parts to an Indian built F-16, which they are unlikely to give up.
The Hornet does not have such luggage.
The U.S. has traditionally been reluctant to provide source code, and also want buyers to sign a set of agreements, which so far India has been reluctant to sign.
If that can be solved, I think the Hornet would be the primary contender to the Gripen E.
If Gripen E was way ahead of anything else, then the Single Engine tender would have continued without this reshuffle.
To me, the IAF wants the Rafale, but knows it is too expensive, and sees Gripen E as the affordable alternative, but the Government wants to reevaluate the Hornet. Maybe due to secretly deciding on Hornet for the Indian Navy.
Ther rest of the alteratives are just for show, and the off chance that France dramatically drops the Rafale price.