I'm going to disagree with advice to paint first and hold off on reupholstering the chairs. You say you've been waiting three years to do this. Selecting fabric can take a lot of time--esp. when working with an open floorplan where you want the colors/fabrics to flow from room to room. You have some lovely fabrics to choose from that can be incorporated into your space in a variety of ways--or even into the adjacent rooms. I recovered my DR chairs last year and am so glad that I did. Mine also were hard and uncomfortable--which you said yours are as well. One thing that was important to me was the fabric not only coordinate with my DR, but my LR since I planned to occasionally move the DR chairs into the LR if I needed extra seating for a party. Personally I found a stripe to be the most versatile choice. I do also agree that you are more likely to tire of a floral or find it more limiting as time goes on. To me, your ivory will always read more formal due to the sheen of the present fabric--not so much the color. If you still like the floral, I would again consider using two complimentary fabrics and use the floral in smaller doses. For instance, you could do the host chairs in floral and others in stripe or solid, or do different backs/fronts as I suggested earlier. Or bring in your floral fabric in a less permanent way via a table or buffet runner. Calico Corners is also really good with suggesting complimentary fabrics. It may be worthwhile to bring in a swatch of the valance fabric and ask for advice on complementary fabrics.

Hmm . . . I like this table, too, and while velvet chairs are featured with it on West Elm, the fact that you have 2 other velvet seating pieces, I would say no. I think a different texture would bring more depth - perhaps even a leather or pleather option. Here is a link to Houzz' contemporary dining chairs: [https://www.houzz.com/products/contemporary-dining-room-chairs-prbr1-br~t_969~s_2103[(https://www.houzz.com/products/contemporary-dining-room-chairs-prbr1-br~t_969~s_2103)

Why are painting the legs black???????????

https://www.amazon.com/ROBDAE-Leather-Suitable-Restaurant-Kitchen/dp/B083FHPFN3 That's one expensive dining chair!