I think there are definitely pros & cons. It is just really hard for me to have multiple infants b/c I thrive on structure & routine & they thrive on spontaneity.
. After 6 mo I think it is easier to get them on a schedule, but the number of naps needed changes every few months & I feel like it's a lot to juggle.
This is the youngest group I've had & my kids range from 8 mo-3 years. It's been hard for me. My DD has a birthday next week & she will be 2. I have two 2 yo dcbs & they will be 3 in June & September. I just noticed about a week ago that I felt like I could breathe again.
I think they are moving from the toddler phase to the little kid phase & it all just goes smoother now. As for outside, I would spend a lot of time outdoors even with the littles as long as they're in the shade. I use a variety of equipment for them outside. Mine love a blanket on the grass with toys to roll around on. I also use a jumparoo. I sit it in the grass so their feet brush the grass when they jump. Exersaucer with tray for picnic lunches. I cover the equipment with grill covers at night to protect from rain so I don't have to move them in & out.
With infants, you will need pack n plays or another safe sleep area... possibly separate areas so they don't wake each other if they are on different schedules. They will play with about anything. I don't buy special toys for infants. They love mirrors! Playing on the floor in front of a mirror is a fun!
I don't know if that answers your question exactly, but those are the things I've found to help with that age group. For myself, I have learned that I'm a one infant at a time kind of girl. However, if you enjoy that age you can make it work. I think it really depends on what age group you enjoy most. I do feel like there's more liability with an infant in regards to sleep practices & such. And if parents put them to sleep in ways you can't mimic (nursing, rocking, in a swing, etc) it is that much harder for the provider. Good luck whichever way you decide to go.