As i understand it a hen has a fixed number of eggs it can lay in its life, if the bird only lays 6 months of the year it will lay for twice as long as a forced hen that lays all year round. it should not affect age of the bird, but it will have a longer period of zero production before it gets to its maxium age. Hybrids have been crossed to help them lay eggs all year round but as this was the sole target of the crossing many strains are now genetically weak against diesease and that is why they often die earlier.
Remember laying an egg takes alot of of the bird whether breed to do it or not (like giving birth everyday of your life) it envolves alot of protein and minerals, through the summer this can take the birds out of condition, i agree that a rest can only be a good thing to get the birds back on top, espiecally as the cold weather hits their immune system hard at this time of year.
As for lighting and how much, remember that birds do need the light to fade slowly so they can roost as said above, easy to do if you add the light in the morning, the light needs to cover the food and water so that they can still eat and drink during the"extra time" (otherwise they will lose condition quickly). As for light intensity around 50-20 lux, you can buy light meters for about £30 but as a guide that is not that bright your desk in an office should be lit with 500lux on the writing surface, a 50w halogen spot with a 45degree beam angle will light a surface 4m in front of the bulb with about 40-50lux.
Hope this helps
By the way i like the idea of freezing he eggs!