Yes, it is fine to have something different in kitchen. Great the front facing windows are treated same, not necessary on the back. Roman shades over kitchen sink can be beautiful.

I agree that the front windows should be pretty similar. I am old and have trouble thinking of blinds/shades as window treatments, especially when they look like paper bags or projector screens. They should serve a purpose for light control or privacy, but almost always look better with curtains.

Particularly disconcerting are brown blinds. I prefer my home to be light and bright. White blinds/shades can work if they are softened with curtains.

Take a walk through some neighborhoods and look at the window treatments. How do they look? Do you see any that you like? You might get some ideas.

In the kitchen, use what works for you -- especially if you'll probably be doing most of the kitchen cleaning. If you fry food, an oily film can eventually build up on the slats of the blinds.

For the rest of the house, do use the same wood blinds, with or without other window treatments covering the top of them when they're pulled all the way open..

I think your window treatment COLOR should be similar, but I personally think you could vary the materials from thick to thin and the type of materials and it wouldn't be obvious on the outside of the house. So, you could have sheers on one window and a heavy damask in another window as long as they were the same color, you won't notice the different from the outside.

From the street does it matter to YOU that the look is cohesive? Many people think it really helps the street view when the window treatments give all the windows a similar look. Lined drapes would do this. Your blinds do that. Who sees your home from the back? If the answer is few or no one--why would anyone care? Some don't care anyway. It is all about how you want your home to be viewed and which look you think gives the best impression.