We also didn’t build a light saber because for that it did seem that they had a hard cut-off of 1 person accompanying a paying builder. When I was taking one kid to the bathroom, my husband tried to ask a cast member what the light saber line was for & as advertised (keeping the entrance under wraps & mysterious), the CM told him it was a “junkyard” which is the cover for the workshop to protect it.
As for the droids, there was always a line to build a droid that fed into the register where you purchase the custom droid & then get the basket to go collect your parts but anyone was free to walk in the multiple entrances and there was no need to wait in line if just purchasing accessories or any pre-built droids.
ETA: We (family of 5) got into the line to build just 1 droid, ended up not being able to choose between the R-series or BB-series and so let the 2 older kids each build a droid (the 3rd one is only 2 & was napping in his stroller through the whole line but woke up in time to help activate the droids at the end). It was an awesome experience & I am so glad we picked doing 2 droids over a light saber (although we do really want to eventually get a light saber or 2 or 3).