Wow....just...Wow. Sigh...the 90's have had their day. Time to get this beautiful gal up to speed!
At this point, you have such a MASSIVE hodgepodge of flooring I am with you on this....get it all out and put one thing throughout. If wood in the kitchen makes you nervous, then feel free to find a pretty tile that you like...but that can wait for another day. That's the day you decide to look at the footprint of the kitchen....again...sweat/worry for another day.
Here's what I like about solid hardwood: You can get it relatively cheap IF YOU CHOOSE the stuff that comes that way. Cheap does NOT mean low-quality. That's not what I'm talking about. I'm talking about 'regular every day' widths of Red Oak (2.75" - 3.5" width; Middle grade) will come in around $5/sf for material. Yep. Solid. Red Oak = $5/sf. If you want White Oak...add $1.50/sf. If you want wider planks like 4" or so, then you are going to add $2/sf. Don't go any wider than 4". The installation costs are ENORMOUS.
Stick with a relatively easy width to install (2.75" - 4.5" width = nail/cleat/staple only). As soon as you go 5" or wider you need GLUE ASSIST = more material costs (add $1/sf) and more LABOUR costs (add $1/sf).
The reason why I'm looking at Red Oak for you: it goes nicely with the wood trim AND the slightly darker/warmer beams. As pretty as European Oak-looking stuff is, it is very pale and very cool in tone. It is very likely you will get a colour/wood clash between the Euro Oak and the pine/fir trim/beams. And that would be very sad.
So...I would go with 3.5" (whatever comes closest in your area) nail down hardwood throughout. I would then pay the piper for the FINISH. Go with Bona Traffic HD. If you want to deepen the warm colours, then go with NaturalSeal or ClassicSeal (red oak doesn't need sealant...but they are often used to add a snick more colour to a floor).
Red Oak with a clear water based finish (without a coloured sealant) looks like dried wheat or hay. It is very pale and very pretty. And very cheap (compared to some of the fashionable widths/woods/colours).
Well worth the $10-$12/sf you will spend purchasing it and having it installed with the expensive Bona Traffic HD. Well worth it.
Q