heard the phrase 'short term pain, long term gain'?. its a small sacrifice to make at this stage. i think you should suck it up, take some of the heavier gear for them, & save the ultra light for later. you will just get frustrated waiting around if you go ultra light, & they could also get injured if they over do it, then you will have to carry them, that would be ultra heavy.
if some of them are of similar build, you could swap the packs around during the hike, this way they can share the weight, get to try out other types/brands of gear as well. going over their gear first before you leave would be the go, just in case there are surplus items.
sometimes letting other people carry the lighter load can back-fire though, & they expect to carry a lighter pack all the time. i did a hike with my wife on Stewart Is a while back. she mainly carried an osprey pack 28L, sleeping bag, clothes, some water & snowpeak ti cup. maybe 3kg total. she thought it was great, 'heaps easier than i thought it would be'... i wonder why? (this is good though, she is keen to go on more hikes, this also means i can get out more). i hope she doesnt expect it to be that light every trip. she did injure he knee later on the walk so i then offered to carry her pack. i am now looking to get her a lighter sleeping bag, then she can carry some of the food, which will lighten me up, even though she wont know any difference. am i a bad husband?
doing more training before you go out would be a great help for everyone. you dont want put these wahine off with a bad experience first up. its too much of a sausage fest out there as it is, the female companion puts a different perspective on things out there. there can be distractions, so watch where you are walking.
it sounds like you have a few miles under your belt. lead them. share the weight, then share your knowledge. any trips after this will only get lighter & better, with a whole lot of new light weight friends. thats when you go ultra light.
have fun but keep it real