You must be so excited! Good luck and hope it all goes well for you. Nothing you gather will be wasted as sounds like it is all gathered with love and care. Hope you enjoy stocking up and making their rooms welcoming with the books and toys etc. We got in some music mags and put them on the beds and put some colourful fleeces on the beds too just to make them look personal and less bare and give the children something to snuggle up to until they felt safe enough to feel at home.
We got the children to make their own pictures for their bedroom doors when they arrived and this was a good idea as it ensured that if they went for a wee in the night they got back in their room safely rather than wandering round the upstairs landing lost and scared! We made a big sign for the upstairs loo too so the foster children knew which door it was when all the bedroom doors were closed. Little things make a difference - but I expect you are already way ahead of us!!