I'll weigh in with a rough guess. I have done each of those walks - none of them could be considered hikes - as part of longer hikes so didn't take notes, but I can pop in with rough figures.
Along the railway from the top of the Lauterbrunnen cable car (old long gone funicular, I still miss ya, but the cable car is fine ....) to the end of the train line in Muerren, anywhere from 20 to 40 minutes to an hour or two or so depending on photo stops, in-or-out of fitness, ogle value, etc. I walked that when the mountains were shielded by fog, and peeped across the valley as I walked at Wengen because it is lower and out of the clouds. Refreshments and cheese dairy about half way, restaurants in Muerren.
Cable car to Gimmelwald and then cable car down the cliff, I usually walk to Gimmelwald and have hiked down the trail to Steckelberg - a fun half afternoon - I would guess that both cable car sections are about 5 minutes each.
I've only walked the Steckelberg to Lauterbrunnen bit when tired as a dog and took, dunno, maybe an hour or so? If fresh it should go much more quickly. Food in Gimmelwald; a snack bar and probably burgers and wurst in the carpark at Steckelberg - gotta feed those hang gliders and base jumpers before they go up for another go, you know - plenty of food in Lauterbrunnen.
All the above is dependent on your ogle factor and fitness, number in the group, walking limitations, etc.
Enjoy your glimpse of the beautiful valley. Next time, stay awhile.