Not discussing the pet's pros and cons but i have a question... why are some of my pets in use when i only use the first 2? Don't understand why there are 3 others in use.
There's something call the Support System. Support allows you to take 2 pets to your squad and further increase your overall stats. You can access this by clicking that arrow on the right, click Box on bottom, then Blue button on right, then last button (customization) and choose what pet you want to put on support. If pet has the same element as the main weapon you're using, it will gives 30% more stats to overall abilities so keep that in mind as you select your pets and weapons.
2 pets each for each main pet? And they use weapons too? Cos i noticed some of my weapons are in use as well.