Those are the only two achievements I need for Morostide battles yet. So...

Where/How do I get each of them as challengers? Any advice on beating them?

Think Felinah can do it? Level: 222 Strength: 554 Defense: 555 Speed: 555 Health: 556 HP: 543/556

You can get them when they are released and not earlier, you might be able to beat the carroim lord if you have the right weapons.

What do you consider decent weapons to take them on with?

I dont know if the weapons on them are gonna change so there is nothing to say about that, But i would go defensive rather than offensive with low stat pets.

Oh alrighty. Thank you for the advice! :D