Are they all of the same metal? If so, I think you can leave them as is. If not, just start shopping for the same metal on the new chandy and find one you love. It will be OK.

Check out overstock.com they have an excellent selection at a reasonable price. I too would make them all the same metal.

I am going to assume that you chose the foyer light yourself since you want to keep it (even though the color and style don't really go with the dining room one) it actually matches the style of the wood one more but either way I would suggest hanging something like this over your kitchen table and just in case you want to change the foyer here is a suggestion for that space too