You could put slipcovers on the chairs, but you would not be happy because they would slip and slide all over the place, despite the padded seats. They would end up looking very messy. Reupholstering those kind of seats are very easy: unscrew them from underneath and staple new fabric in place of the old. Easy, peasy.

I don't think that chandelier goes the best with your chairs. It's too ornate. I think the chairs are the main issue here as your buffet is a completely different style than the chairs, too. Probably figure out the chairs before you go any further.

If your husband like cushions on the chairs and you don't like the present ones, recovering chair cushions is easy.

I would not do slip covers with kids unless you plan on washing them everytime you use them Get some fun fabric and make new cushion covers and check out Chilewich for great floor mats that you can take outside and hose off when they get dirty.I think the drapes are fine I would like to see a bigger piece of art hung lower and with some more color. Why not look for a light that actually puts light on the table instead of the ceiling.

If you replace your chandelier, the bottom of it should be about 30-33" above the table. You will get more light for the table rather than the ceiling. Your table and chairs look to be Mission style, so an oil-rubbed bronze wrought iron with simple lines would be a good choice.

Why not do an indoor/outdoor rug instead if you don't want a rug they are easier. there are lots of different options now and your dining room seems to need one. Below are also some chandelier options.