A few questions

I just had a few questions about an uncoming trip to Tokyo/Kyoto/Osaka if anyone had some time to answer them for me I would really appreciate it!

1.)If I buy a JR Green Pass do I have to reserve seats or can I sit anywhere?

2.)If I decide to buy the ORDINARY Pass what are the chances I won't be able to find a seat or sit together with my friends who are traveling with me? Basically how crowded will the train be?

3.)I am arriving May 7th to Japan, will the crowds from Golden Week have died down by then?

Thanks in advance,
Hannah

1) Yes, green car is reserved seats only. Good thing about the green car is that not many people ride it so you're chances of getting a seat are pretty good.

2) You can reserve seats hours in advance to make sure you're able to get seats together, though it will be difficult to be seated together if you're traveling with a large group.

3) Yes, by the 7th, the crowds will be back to normal.