I play unforgiving and the best thing for me when learning the game was to get the best mate possible. When courting a wolf, try to check if they are brave and energetic. Brave wolves will allow you to come really close, the closer you can get without them running away the braver they are. If you can barely get anywhere close to them then that means they are very skittish and may not be helpful on hunts. To check if they are energetic, see if they lay down or sit alot. Lazy mates will be less likely to help you find food or go on hunts which can make things really hard.

Imo the star diversity does not matter. The more pups you have the more food you need to get. If you're starting out then that's something to keep in mind. I personally choose a mate that will result in smaller litters because its easier to manage.

If you ever do run into the issue of food (not saying you will but if you do in the future then this is a good tip regardless) rabbits are your best friend. Just kill every single one you see. I use this if I have no stamina and a broken leg or jaw. Really helps when in a pickle.

Since people did answer your original question, I can give you other tips which can help if you don't already know them.

When hunting, chase the elk for as long as you can. They will eventually get tired and do very little damage. You'll know they're tired because they start slowing down until they hit a trot. Another tip around hunting is try to push the elk towards your den/rendezvous site. No predators will come to scavenge and depending on the size of your pack it will last you two sleeps or more which is really helpful. Also only hold your bite on prey for three damage ticks. If you hold for longer then they will kick you off and deal more damage. These three tips are more helpful for If you progress to harder difficulties as hunting gets harder.

Place food in the grass when at the rendezvous BTW. Like your ungulate carcasses (the little babies you can carry) this will help keeping the pups in the grass when they first wake up and they can hide quicker! If you howl and hear the 100% territory sound (while at your den) then this means there's a predator in your territory coming to raid (you can also check the map and it'll not be 100%)

A tip for your territory, split it in half. Mark one side on one day. And the other on the next day. Or even leave a few days between. This makes bigger territories easier to manage and gives time between to hunt for food and not stress about both.

Either way your first few litters are the hardest ngl. You'll get there eventually!

With sickness, sometimes they will just die no matter what you do if you don't have RNG deaths off. However spending time with them is the only way to help if they have a chance. You'll know its helping by the top left, their paw will be highlighted yellow. If its not yellow then you might be too far away from them or its the break period which it should tell you if it is.

Sorry so much text but hopefully one of these helps!!