I would guess it something like with humans in the womb: they are attached to the yolk by the umbilical cord and the yolk, I think is attached to the membrane of the egg. Within those limitations I would guess it can move around to an extent.
the baby geckos belly is attached to the yolk by an umbilical cord and the yolk is attached to the membrane of the egg. at which point the yolk is attached to the egg varies, i candle my eggs and they are all attached in diffrent places.
yes the baby is free to move around but dosemt tend to when its young but will be more active as its getting ready to hatch. i have seen some of my eirlyer eggs flinch and wiggle when iv candled them but so would i if some one woke me up with a bright light LOL
you should never turn the eggs because this could break the connections holding the yolk to the egg resulting in the baby being crushed by the weight of the yolk drowning it. POOR BABY