shinkansen questions

Hello all, this is my first time posting. I`ve been staying in Fukuoka the last few weeks and have decided to ride the Shinkansen to Tokyo before going home via Narita aiport. My question is, taking an ordinary Hikari train, presumably on the Tokaido/Sanyo line, from Hakata station... would I need to transfer at any point? Or are trains from Hakata able to go straight to Tokyo? Also, assumedly, the station I should be ending up at would be Tokyo station in Marunouchi? Is it easy to hail a cab to one`s hotel from there?

Oh yes! I also hear you can reserve seats on the shinkansen ahead of time? Is it possible to do that with a JR Rail Pass? I don`t know yet what time train I`ll be taking...

I`d be really grateful for any assistance. Thank you for reading my questions and I apologize if they are insultingly menial.

My question is, taking an ordinary Hikari train, presumably on the Tokaido/Sanyo line, from Hakata station... would I need to transfer at any point? Or are trains from Hakata able to go straight to Tokyo?

There are no direct hikari trains. A transfer is required along the way, typically at Okayama or Shin-Osaka Station:
http://www.japan-guide.com/e/e4802.html

Also, assumedly, the station I should be ending up at would be Tokyo station in Marunouchi? Is it easy to hail a cab to one`s hotel from there?

There are taxi stands in front of Tokyo Station with hundreds of taxis waiting for customers.

I also hear you can reserve seats on the shinkansen ahead of time? Is it possible to do that with a JR Rail Pass?

Yes. It is even free:
http://www.japan-guide.com/e/e2361.html