If Tolsimir is still on the battlefield when its enters-the-battlefield trigger resolves, its last ability will trigger as Voja is created.

You may put Tolsimir's last ability onto the stack without choosing any target. You'll just gain 3 life. However, if you do choose a target and the target permanent is an illegal target by the time Tolsimir's last ability tries to resolve, the ability doesn't resolve. You don't gain 3 life and no creature deals or is dealt damage.

If the Wolf that entered the battlefield is no longer on the battlefield as Tolsimir's last ability resolves, no creature deals or is dealt damage, but you do gain 3 life.

Tolsimir, Friend to Wolves has a different name than Tolsimir Wolfblood (from the Ravnica: City of Guilds™ set), and Voja, Friend to Elves has a different name than Voja, the token created by Tolsimir Wolfblood. Since the "legend rule" only cares about exact English names, this means you may control all four of these creatures at the same time.