Can I write about one subject at more than one outlet?

I am a freelance writer. I’ve had some success, but I’m relatively green in some of the pitching/placement processes:

I recently sent out an article pitch and received mostly positive feedback, ultimately landing a few potential placements. In fact, three were interested. In my original pitch I outlined three potential story lines, so there’s lots of space for different angles, particularly in the interviews I could include and other historical takes. In other words, I could write without repeating.

Of the three that are interested, one stands out the most and I’m committed to it—it’s international and in print and will most likely pay the best. The other two are reputable as well (and online) and I’d like to build relationships there. As a freelance writer I know this is ground for both opportunity and careful walking. My question is – what do you suggest? Should I reach out to the other two and let them know of my commitment(s)? How could I state this without scaring them away…?

As a freelance writer, I know one needs to squeeze out all the miles one can get on a gas tank…and I want to learn how to do it well, professionally. Please help.