Well, I expect that all the super-tele prime RF L lenses in the future will have IS. The 135 is in a mid range so that I could see the f1.4L not having IS, while the f2L might (50-50 chance) have it.It will probably closely match the 0.25x magnification of the Sony 135 GM, I would not expect any better and I would not expect IS either, none of the RF L primes have it, they aim for maximum image quality with a suitably fast AF speed.
Regarding pricing, it will be over 3000$.
I'm guessing the max mag. for the 130 f1.4L is between .12 and .2 X, with the 135 f2L between .2 and .3X
I'm guessing the price of the 130 f1.4L is over $3k as well, with the 135 f2L between $1899 and $2199.
(time will tell)