for kitchen , just go with chrome.

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For the kids bath, I would take the shallow cast iron, since that's the most durable, and I'm guessing that's probably an alcove tub which means more of a hassle if you need to change it later.

If it were me, I'd go for the soaking tub in the master, but I think most people would opt for the air tub over the whirlpool these days.

I'd also opt for the cast iron for the kids (that's what I just put in mine), and the soaker in the master. I'm not crazy about the whirlpool/air bath thing, I just don't think I'd really use it enough.

I'd also vote for chrome--I like satin nickel a lot, but I worry that in 10 years,people will look at it and say "That's so early 2000's." Chrome is classic and timeless.
Just my $.02. Good luck!

I would do Cast iron in the kids bath, it is more durable. I went with a slightly deeper than shallow, but not really deep one in mine.

I'd choose either the air tub or soaker. the whirlpool ones with water circulating I feel can grow stuff in the lines. We actualyl went with a large cast iron soaker Kohler "tea for two"

if I did it over again, I might skip it entirely and go for a larger shower. but I don't think I'd get a whirlpool.

I went with Chrome on the kitchen drain. its durable, and in my kitchen in a stainless sink, Chrome seems to match the sink. Chosen for two reasons. I hear some chemicals will take off the finish of "colored" drains, not that I plan on using anything too harsh but who knows. Also, the upcharge for the fancy drain was absurd

If the kids are going to use the bathtub as a tub/shower, then a lower tub edge will make it easier for them to step in and out.

The drains should match the sink, not the faucet.

You should choose the tub option that you think you will use the most. I have a whirlpool tub and I love it, but I use it quite a bit.

for the kitchen just use satin nickel there are becoming more popular these days

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