Quite honestly, having two bunnies from the same litter doesn't make them more or less likely to get along when they get older. Before puberty, pretty much any two bunnies will get along quite well, cuddle, etc. However, when the hormones come out when they mature, even littermates can turn against each other. Of course they could get along perfectly fine too..it's just that a littermate pairing is just like any other, and you never know how it's going to turn out.
If you decide on adopting two baby bunnies at the same time, you'd have to be aware that there is a possibility you'll have to separate them when the hormones come out, and re-introduce them after the neutering procedure. In the meanwhile you'd have to house the two separately; two cages, two sets of food/water/litterboxes, etc. I particularly warn against adopting a baby male/female pair and housing them together from the get-go, because bunnies can mature quite quickly and the buck could impregnate the doe (yes, even siblings) even before you realize that they're old enough.
To have two bunnies, I'd suggest starting out with one first. Build and strengthen the bond between you and your bunny first, and when you're ready and your bun is neutered try bunny-dating to find a second.