The landing gear lever is rather prominently featured in the 787 in a panel central to the cockpit layout so that either pilot can easily reach it. For decades and across many manufacturers, the landing gear lever has traditionally featured a knob that deliberately resembles an airplane wheel. It's very hard to mistake it for anything else. It's actuated by simply moving it up or down.

The fuel control switches are behind the throttle stalks above the handles to release the engine fire suppression agents. These switches are markedly smaller and have guards on each side protecting them from accidental manipulation. You need to reach behind and twirl your fingers around a bit to reach them. Actuating these switches requires pulling the knob up sufficiently to clear a stop lock before then rotating down. There are two switches that were activated in sequence and in short order.

The pilot monitoring is responsible for raising the gear in response to the pilot flyings' instruction.

I would find it very difficult to believe this was a muscle memory mistake. At the very least, I would want to more evidence supporting such a proposition.

This idea strikes me as even more unlikely than someone shifting their moving vehicle into reverse while intending to activate the window wipers.