Is there anything I need to do to mark my chosen squirrels the next alpha pair when my alpha pair die?

Your beta male and female will become the new alphas once your current ones die

In order for a squirrelto become Alpha, all they need is the highest dominance in their pack. Alpha Females need to have higher dominance than all other females in the pack, and Alpha Males need to have higher dominance than all other males in the pack. Dominance is all that's needed for a squirrelto become Alpha.

Also what Ducky said. Whoever has the higher dominance under your Alphas is basically "next in line" but if they all have they same amount of dominance when the/ an Alpha dies the Betas will become Alpha. The next Betas would be randomly chosen from the Omegas I believe, if all of your Omegas have the same amount of dominance and you have more than two of each gender of course.

Affinity between Alphas doesn't matter, as Alphas become Pair Bonded. So if you look at one of your wolf's Affinity page, it will show all of the squirrels as "Like, Strong Like, Dislike" etc, but your alphas will show as Pair Bonded. They don't like nor dislike each other. As soon as they become alphas they are mates.

Ok, thanks!