Going forward if you do not upgrade to El Capitan and decide to keep Aperture and Lightroom both, then yes you can keep both of them as separate editing applications without interfering.
When you will install and start working with Lightroom, you will get a fresh empty catalog and you can start importing your new images in it or your complete Aperture Library if you want :
If you want to selectively import images from Aperture to Lightroom, then you can select those images > export to your hard drive and then, import in Lightroom.
You can begin with a trial of Lightroom to see how it goes.
"Would there be a way to just stop using Aperture, and instead just start using Lightroom with a brand-new catalog and NOT import my managed library?"
This makes lots of sense. You can build up your Lightroom experience while keeping access to your Aperture work. If you eventually bring the Aperture images into Lr, you will then find the job easier.
I don't quote the rest of your post, but I would agree with your approach. I think it's important to set a clear date and not try to be too clever. So if the photo is taken before today, it's Aperture. From today, Lightroom.
I'm correct in my assumption that the only way to import files while preserving the adjustments from Aperture is via a Tiff, correct? There is no way to import them as jpegs while saving the adjustments?
I believe Aperture allows to export in Tiff, jpeg, png and PSD and you can choose the format according to your choice.
Yep that I what I'm thinking. It seems silly to try to force my aperture history into the lightroom world. My only hope is that an eventual upgrade to el capital won't screw up this plan.
Now onto figuring out lightroom!!
Thanks for the help.
I think that in the long run, all photos should be in the same "organizing" program, not some in Lightroom and some in Aperture.
Today, and in the next few weeks, you will not have any trouble remembering which photos were taken before 2/23/16 and which photos were taken after. But as the years go by, that information will no longer be in your memory, and having some photos in Aperture and some in Lightroom will simply slow you down.
Furthermore, if you leave the photos in separate applications, there's no way to do a search and find (for examples) all photos of a certain individual, or all photos taken in a certain location.
So using one "organizing" program has lots of benefits, and as far as I can see, no drawbacks.
except given that almost every photo in my library is an edited JPEG, the idea of transferring all of those photos and losing the adjustments sort of scares me.
if there is a workaround for this, I'm all ears!!!! From what I've read if I use the plug in to transfer my managed library, I will lose all of my adjustments.
I mean, in the big picture I totally agree with you as far as having all of my images in one place. Aperture seems as though its at a dead end, although if the program continues to function at a basic level without updates there are a lot of things I really like about it. I also have a new baby and not a lot of free time, so knowing I have aperture to fall back on is comforting. Walking into lightroom and only having short bursts of time to get to know it is sort of overwhelming.