I'd scatter some now but leave some seeds at one side in a brown paper bag until the spring and then put them out then, see which ones take best. You can always get some seeds off the ones which do take and scatter again next year at a time which has worked best.
I scattered some in Spring and they have come up lovely, some going to seed a little now, the poppies. I have left the grass to grow, it moves about lovely in the breeze/wind. So many people want to cut it down but I like to see it as nature would have it. I am going to take up sections and plant some more wildflower seeds and so that eventually it makes a meadow. I have done a seating area in a different part of my garden, making it into a fairy garden with fairy lights, plants and trees from my other home, driftwood and a tree stump and some fairies and a unicorn and my tiny minions.
Did anyone see the Autistic Gardener? The lying down man which they made was absolutely brilliant and something which I have never seen before. Looking forward to seeing next week's programme.