I agree with Shawn, you're at an exciting point where your first shrimp are trying to establish a colony - let them at least get a few batches of shrimplets out so the colony can start to get established before you risk adding anything else.
Bettas often like to eat shrimp, and will likely send yours into hiding. Otos won't bother the shrimp, but essjay is right about them needing a group, which means a lot of algae needed, that being hard in a small tank, and importantly, they're competition for food against the shrimp, which can discourage breeding.
You've got rili shrimp which are the best to watch with eggs! Your girls are early in the process, once they move their eggs to underneath, since they're clear in the middle, you can really see the eggs well and it's great!
I have a photo of one of mine somewhere carrying eggs, but can't find the photo right now, so pinched this one from google images to show you how clearly you get to see the process!
If you search on youtube for "cherry shrimp hatching" you can find close up and slowed down video of the process, and the female flings the shrimplets away, it's pretty amazing to see the videos! Shrimp are very cool little critters.
Don't be alarmed when you find moults like this lying around too, first few creeped me out a bit! But it's a sign the shrimp are growing and moulting well, and you soon get used to finding them.
Let them get settled in first and enjoy the process, you won't regret it! They're great little creatures, and so helpful for tank clean up. Otos are wonderful fish too, one of my favs, but I'd wait a while, and grow some algae rocks in advance before getting any. Mine like the repashy soylent green too, but not all will take prepared foods, at least not at first.
@Slammin’ Aquascaping breeding otos is one of my fishkeeping dreams! Please please pm me or make a thread telling everything about how you did it! I want to learn and breed some too!
Otos are wonderful little fish, but delicate, wild caught, and have a very hard time with being captured, warehoused, shipped, adjusting to store tanks and then again to home tanks, and big losses are common, so recommend reading up on them and really preparing for their arrival to give them the best shot of making it.
I think I managed to get mine to the point of spawning before, but not success with fry yet, sadly.
