Keep it simple.
"a. When Joe arrived, I'd made some coffee," doesn't make sense to me, because the phrases are unrelated. "I had made some coffee before Joe arrived" sounds much better.
"b. When Joe arrived, I made some coffee," is perfectly clear usage; e. g., "When my friend Joe arrived at my place, I made some coffee for us to drink together."
"c. When Joe arrived, I was making some coffee" is not necessarily an interruption. "Making coffee" is almost always at least partly automated or passive and does not require constant attention, even if you are just boiling the coffee grounds over a campfire; once boiling, you stir the grounds and move the pot to a cooler spot on the fire to let it simmer for a few minutes. On the stove, you turn down the heat to simmer. With a drip-coffee maker, you pour the boiling water over the ground coffee in the filter and let it drip into a cup beneath. Coffee-making machines often require no attention during the process at all. So "When Joe arrived, I was making some coffee" simply describes what you were doing when Joe arrived.
"d. When Joe arrived, I'd been making some coffee," sounds odd and unnecessarily wordy to a native English speaker. Again, "I had made some coffee before Joe arrived" sounds much more natural.