I've just returned from a trek of Toubkal - my friend and I paid about £250 for a guide, mule, muleteer, porter and cook for three days, including all accomodation. We booked in advance as not sure what it would be like - but you can walk into the guide office in Imlil and sort one - could take up some of your short visit though.
The problem we found of travelling in winter was the amount of kit we needed to tackle the mountain - and its VERY cold in the evenings so you'd want a good sleeping bag, lots of warm layers for the evening - unless you really like roughing it. We stuffed our essential kit in one bag and the mule/porter carried it. The locals do find it odd if you carry huge bags.
Food is available at the refuges if you travel independantly and pre-book (both have websites - search Neltner or Mouflons refgue).
Most of the places in Imlil will be able to store your luggage - ours did happily in a locked room.
There will be other people about, especially once you get to the refuge, but how they feel about you joining them to the summit may deend on how much they've paid for a guide or if independant.
We felt we could have easily done it without a guide, though the altitude did make it hard work on the first day, but we had the whole afternoon to relax.
The guide did all the organising with the Refuge owners (whose English was limited), and even sorted out a change of plan as we were keen to do as much as possible, booking additional accomodation for us in a Berber village.