The Charouz Aston Martin is designed and run by Aston Martin Racing, it's significantly different from a standard Lola. The new car will be an LMP1 Evo, which are similar to current LMP1's but with roadcar styling. The new car has been designed, Prodrive don't have the capability to build the chassis in-house, so that could be outsourced to someone like Lola, thereby continuing the working relationship. Charouz have apparently also ordered a second Lola so it will be intriguing to see if the factory Aston Martin LMP1 is significantly different from the current Charouz Lola.
Jaguar personal were at Le Mans, that's were the rumours started, Tata then stated in a report they are looking to return to Le Mans.
Initially GT2 was mentioned, but it seems LMP1 is what they are looking at after a DSC article and a few other off the record hints.
Talk of any GT1 programs is premature as current cars are only legal for a further year or two. GT2 is more stable as any proposed changes are only minor, so the likes of the new BMW M3 GTR will have a long shelf life.