We have two kids at two different DCPS charters (but not this specific combination). It's been fine, I'm happy that the kids are each at a school that is a better fit for them.
Logistics: They mostly do the commute on their own. They also have separate friends, etc., but they probably would have either way.
Latin's vacation calendar does not mesh with DCPS, so might not mesh with Basis's schedule either (or maybe it would). Our two schools have two different spring breaks, which has been annoying, but not worth switching schools for.
Sometimes it helps to have perspective by seeing how two different schools do things differently. But you don't get as much of a benefit of knowing more stuff with your younger, if your older didn't go through same teachers/curriculum.
Can't really think of other issues. Having to be on two separate school emails/listservs?