I think you should do the same LED temps throughout the kitchen. I don't know if 300k will make a difference. My installation is the 2700k, the cool option would have been 5000k in my brand which is noticeable to me.

For me the colors of LED's have a different look compared to incandescent or CFL's. I have a brand called Diode LED. I chose them when I saw a nice display at my electrical wholesaler/retailer. This company also has an online retail business called Elemental LED. When I talked with Elemental LED about this very question, they recommended staying with the warm white. The fellow I talked with said he had warm white throughout his house. He said the cooler white is better for retail displays/stores. So I went with the all warm white (2700k).

I don't have an opinion on mixing.

I have 3000 K lights, which were the warmest I could get in the brand I chose. I like them a lot, but wish they were a little warmer. Thus, I would recommend the 2700 K lights, if all else is equal. (Like enduring, I don't think there will be a big difference between 3000 and 2700 K, so I wouldn't make a choice, say, between brands based on that.)

Thanks, the electrician said he'd go with 3000 (and tell me if the rest makes sense) b/c with dimmers I can lower the intensity.

I'm no expert but just b/c you DIM a light would that change the temperature??

Also,
Are the bulbs replaceable I assume if I want to change it after?

No, that doesn't really make sense. Light output (lumens or watts) would be affected by dimming, but (especially with LEDs) the colour doesn't change.
IMO I would go with 2700, I tried both for flood lights in my kitchen and enjoyed the yellow colour much better with the 2700K rather than 3000K.

Co-Co is correct. The color temperature DOES change for incandescents upon dimming, but it does NOT change for LEDs.

thanks!

The color/temperature is named according to the color of black body radiation. When you dim led, the intensity changes, but not the color/temperature.

My DH says lights shouldn't be yellow- we went with 3K vs the 2700 that I was first considering and a good thing as I blew it by putting in 5 inch cans which have less flexibility. oops but saved.

a2gemini- We did the 3000 and I think it looks good!

What do you mean about the cans???

The cans are 5 inches instead of the standard 6 inch - I was thinking of using the new GE bulbs but then didn't like them. We really like the 3K version - but it might take getting used to if you are used to "yellow" incandescents.