There are several other McLaren models I'd prefer to see before the Elva, such as the regular P1, the Speedtail, or even the F1 LM.
Anyway, here were my Ford picks:
1. Focus RS Mk.III
2. Mustang Mach-E
3. GT40 Mk.II Race Car '66 (I think the other GT40 Race Cars in GT were based on other iterations of the GT40.)
4. Thunderbird '55
5. [Any third-generation Mustang, unless one has already appeared in GT, in which case, I would instead pick the Ford Mustang Mach 1 '21, as it's a facelifted version of the sixth-generation Mustang. After all, GT6 ended up having both the pre and post-facelift versions of the fifth-generation model.]
My Callaway picks (I actually live just a few minutes away from their international HQ!):
1. C16 Coupe
2. C21 AeroWagen
3. C7
4. "SledgeHammer Corvette"
5. C4 RPO B2K
I'd wait for more cars in the LMH and LMDh classes to be revealed in the real world, and then have a ton of them added to GT (whether it's a content update for GT7 or a future installment entirely) as Gr.1 cars. Those two classes offer tons of opportunities for various automakers to have either more contemporary Gr.1 cars like with Ferrari and BMW, or even be in Gr.1 at all, like with how Lexus is interested. That's before we get into potential DPi racers, like those from Mazda, Acura, Cadillac, and Nissan. I'd love there to be more Gr.1 options in general, both in regards to automakers having more than one Gr.1 car, and in regards to more automakers having even an option. And hopefully, more of the VGTs will offer automakers a Gr.1 car, too, like how I think the Lamborghini VGT could very well end up there, considering its shape and power figures. I could foresee Lamborghini having three Gr.1 cars: the VGT, the Countach QVX from the Group C era, and their eventual LMDh car.
But honestly, when it comes to Ferrari, I'd be thrilled for them to get a Gr.1 VGT, to compliment their eventual LMH racer. Heck, I think the LMH car would be enough for Gr.1 representation - I just wanna see what a Ferrari VGT would look like, now that Porsche and Lamborghini are joining in GT7.