Coasting to a stop in higher gear
 

So I'm still in break-in period, so my question is in that context.

When I slow down to a stop, I keep the car in whatever gear I was running in and use brakes to stop and then when revs get to about 1500 and I'm down to about 10mph or so, I step on clutch and stop.

Is this lugging the engine?

I'm using no throttle during the coast, and if I need to accelerate again for whatever reason, I always shift to the right gear before giving throttle.

Sounds fine to me. I wouldn't worry about it. If you're not on the throttle and the engine is above idle, it shouldn't be firing the cylinders anyway.

Actually if you allow the engine to brake the car, it is not providing any gas, so the cylinders are not firing.
If you take it out of gear and coast, the ECU will provide fuel to keep the engine from dieing.

right... if you take it out of gear the engine will drop down to idle, then it will start firing to keep it running at idle. Until it drops down to idle, I would imagine that it's not firing (though I can't say that with 100% certainty).

Drive like us stole it, that's my break in

No, as long as the gear isn't pulling the engine RPM below idle, you're fine.

I would personally recommend learning how to rev match and downshift properly, but only if you're interested (btw it's fun). This is not just for performance driving, but could help if you need to scoot out of the way of danger, being in a gear/rpm that can actually move you quickly (instead of 6th gear at 1000 rpm, where you'd just lug the engine to death and not accelerate).

lugging only happens when you try to apply throttle at low RPMs. Coasting until right before idling/stalling RPM's is fine, if not recommended