International Flight/Checking luggage through

If it's all on the same ticket, then yes. You will have to go through passport control/security in London but will not have to pick up your luggage until you go through Customs in Edinburgh.

You will also know this during check-in at Louisville, they will tag the bags and tell you, you should see the "EDI" on the tag and your claim tickets.

Lets hope issues have settled down at Heathrow by your trip, might be prudent to put a change of clothes, or two, in your carry on item. (plus the normal cautions about medications and other critical items)

Will I be checking my luggage all the way through to final destination Edinburgh?

Maybe. Depends on your ticket and the airline(s) involved.

All on a single ticket? If not, the answer is no.

All on the same airline? If not, the answer is MAYBE.

Most airlines will do checked bag transfers to a partner airline (called "interlining"), but a few won't.

If there are two (or more) airlines involved and any of them are not "partners," then probably no transfer of checked bags (that would probably be on two separate tickets). Best case: You're flying all the way on American+British Airways (which are partners).

Bottom line: Check with the airline to be sure. And yes, always take a look at how your bag is tagged -- make sure you see the destination "EDI" on the tag -- before it disappears down the baggage belt.

Even if this were on the same itinerary meaning the same ticket, I would not check in any bag because the chances of your bags making the 3 remaining connections right now are slim especially that you are going through Heathrow. The mishandling of bags worldwide is horrific currently. Will you be able to spend your entire trip without the checked luggage if anything is lost? This is the question you must ask because the chances of an airline transporting the luggage to your destination in Scotland after the fact while you are still there are also slim to none.

Because I'm changing at Heathrow, I'm sending my suitcase to my destination with Send my Bag, which uses FedEx and DHL

I agree with Continental! I’d avoid checking with those transfer points, especially London. BTW…I totally understand that itinerary because I, too, fly from an end of the line airport and have 2 airport transits to get to my final destination next month.

Are you traveling with others? I ask because this trip might be a good one to cross pack with someone…a set of your clothes in their bag and vice versa.

Thank you. I appreciate everyone's input and advice!

I would not check in any bag because the chances of it not making the
3 remaining connections right now are slim especially that you are
going through Heathrow.

"Slim" is an overstatement. Less certain than a few years ago maybe.

You have good answers to your question (all one ticket, then yes most likely); but as a comment, I transited through LHR on July 3 to EDI and back again on Aug 8 (was that only yesterday?), with my ticket through American, partnering with BA. (Friends did the same with Delta.)

Your mileage may vary (and obviously people are having trouble) but I had no issues with my checked bag. With a late-arriving flight into LHR on July 3, I missed my EDI connection and had to wait - but my checked bag followed right along with me. Yesterday I only had 90 min for my transfer and spent almost 60 min of it waiting for my next flight. No problem till I got back to my final connection at DFW. 🤣 I will say I liked having my Apple AirTag to follow.

Edit: Pam is right that this is a good year to make sure you have enough with you to manage a couple of days in case it comes to that - either time for your suitcase to catch up or time to buy something new if it doesn’t.

About 3 weeks ago LHR had a major melt down due to equipment failure and thousands of bags didnt make their destination.

That is fixed, but they are are doing 85% of pre-COIVID traffic with 70% of the pre-COVID staff so things still arent great.

But given the extreme attitudes about checking bags, maybe enough will do carryon only where the short staffing will have a better time with it

If I were going someplace where I knew I would be for 3 or 4 days and I had to check a bag, I would; less than that .... ehhhhh...