Hi E. :-)
Do you have any of those "do it yourself" pottery studios around you? They are the BEST for gifts and last a lifetime! Both ages will be able to draw/paint and it comes straight from the heart :-)
Also.. the older child may be able to make her a "necklace or bracelet".. buying some simple beads and stretchy string to do so.. the younger one could do this as well but would need strict supervision.
If you don't have these possibilities around you, how about going to a local art store, purchasing a small size canvas (2) and a few tubes of acrylic paint and paintbrushes and let them go to town! Also will last a lifetime.
When my daughter was 5 we made AMAZING cards! We purchased white glossy paper rolls, finger paints, and opened them up and let the kids just smoosh in the colors and paint, swirl, dance across and around the paper. Lots of different colors and several kids working on one piece of paper to fill it up... when it is done and dried, you take a "template" that you have cut out, like a picture frame, the size of the face of the blank cards you have purchased.. place it over the "whole" painted glossy white paper and you'll begin to SEE amazing creations pop right into your view! When you like what you see, you take an exacto knife, cut "inside" the template and take out the perfect sized piece and then glue it to the front of the card. You'll also need to buy a thick but soft rubber mat, they sell them at the art store.. tell them what you are doing so they understand. You'll place this mat "under" the area you are wanting to cut out of the main painted glossy page, otherwise, you'll cut right through to your table, or floor, or wherever you are doing this cutting out.
THEY WERE SPECTACULAR!
Have fun,
hugs,
A. R.N., Energy Medicine Practitioner