Looking forward to seeing which of the many suggestions you end up using.
I love a good rub that flavors the outside of the meat well. If I want some deeper penetration >ahem< 
, I sometimes stab a roast with one of my large silver fork’s sharp prongs, and make a bit of an effort to rub it all in… but given your vast experience with roasting & smoking lamb, I’m sure you are well versed in seasoning your meat just right 
I did that with my Easter lamb. I had the olive oil, minced garlic, minced rosemary, s/p and lemon zest that was rubbed all over. BUT I also cut some slivers into the roast, and then shoved some of the oil/garlic rub into those slivers as well.
And even though I just had lamb a week or so ago, now I want a lamb tagine or a Shepherd’s Pie with some of the hunks of the roast I cut off and froze. Gah, I 
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I’m a lover of all meats, but lamb & duck are way up there, fo sho 
Dijon/rosemary/garlic.
Scanning the spices, they’re components of baharat or garam masala or ras el hanout, and the rest is pretty standard for middle eastern / south asian meat preps (ginger, garlic, paprika / chilli powder.
So I don’t think it’s as much plagiarism as you might suspect 
— just cultural spice blend commonality.
I’ve done mustard/choose your herb or spice variation here crust many times. Had it first as a much younger Meekah while a dinner guest of really good cooks. I suspect Julia Child was in that mix somewhere.
Lamb tartare
Loin is such a delicate cut of meat that we dont do anything special with it in the cooking. Salt, pepper, a light touch of oil and that’s it. Make a nice sauce to go with it - pretty much anything that you’d make for loin chops is going to work. Mint sauce would be the classic in this house
Our S-I-L’s favorite lamb prep uses a Uyghur-inspired rub.
1T red chili flakes
1 T szechuan pepper corns
2 T cumin seed
1 t fennel seed
1 T kosher salt
1 T granulated garlic
2 T vegetable oil
Coarsely grind the chili flakes, szechuan pepper corns, cumin, and fennel. Add kosher salt, granulated garlic, and vegetable oil to make a paste. Slather on the lamb and refrigerate at least 1 hour, or up to overnight. Grill over hot coals, turning as necessary, to your desired level of doneness (but if you go past medium, you’re a philistine).
I usually do this with a leg, cubing the meat into 1" chunks and packing it onto skewers. It’s really good in some kind of flatbread topped with a yogurt-based sauce (yogurt, lemon juice, cumin, whatever…).
Mint chimichurri on lamb I have never tried; but that sounds like a perfect match.
Anyway you cut it/cook it, lamb is my FAVE!
Also @linguafood. Mint leaves lend a good flavor to lamb and lamb sausages, and to sauces that accompany them (edit - I always put minced mint and dill in my tzatziki). But I seriously dislike mint jelly. One of the reasons my wife dislikes lamb is the smell and taste of the mint jelly her parents always served with their annually-prepared, over-cooked and under-seasoned leg of lamb.
The first time I made a butterflied leg of lamb for them I’d had it in the fridge on yogurt for a few days then another day with a salt/garlic/rosemary rub, and I roasted it on the grill with just a light touch of smoke. As they sat down to eat my FIL asked “Where’s the mint jelly?”, and I engaged my mouth ahead of my brain and said, “Mint jelly is to mask the flavor of poorly prepared lamb”.
Oops. (But in my defense, this was before I knew their personal history/backstory).
I don’t think I’ve ever had the misfortune of being served mint jelly with lamb - isn’t that mostly a British thing @Harters? My PIC, who has an Armenian background always adds mint leaves to his marinade for lamb kebabs (he uses trimmed chonks of leg, generally), along with rosemary, thyme, oregano, onion and TPSTOG).
As for tzatziki, I find any amount of mint overpowering.
Tzatziki should always be mint free.
Looks like the Cypriot version uses mint - perhaps the Turkish influence / cacık? I really don’t care for it in mine, but am pretty generous with the fresh dill 
Not a fan of mint in anything tbh, but fresh dill I like.
I’ll have to think about where and when I like it. It has to be chopped very, very finely, otherwise it’s like eating toothpaste flavored leaves.
ETA: peas. I like mint with peas 
Minus the mint, the Cypriot tzatziki is pretty much how I make mine. I don’t buy a lot of fresh, soft herbs because I usually throw most of it out. 
Interesting. I use the garlic sparingly, after having gone a bit overboard once for a ME-themed party, and the tzatziki got mighty garlicky over the course of the evening. I stick to one big or 2 tiny cloves at the most. I also use RWV instead of lemon, and a splash of olive oil.
Probably. Although I’ve only rarely come across it. Mint sauce (as I mentioned upthread) is much more common in the UK. The sauce, at its traditional most basic , is nothing more than mint, sugar and vinegar. Again, traditionally, the vinegar is standard malt vinegar. This is a very old sauce where wine vinegars would not have been widely available hence its very acidic nature is softened by the sugar.
Jellies such as redcurrant or crab apple are much easier to find here, than mint. By the by, we’ve just returned from a cruise on an American ship where mint jelly was served to Mrs H with a lamb dish. She thought it was horrible - just sugary gloop with no flavour of mint. And, no, I didnt try it for myself.
It does sound like some of the more ancient sauces, going back to Rome, even.
