Tateyama Kurobe Option Ticket

I need help to understand how to buy the Tateyama Kurobe Option Ticket ( 9000Y ). I am going on the Alpine Route on 17 April 2018. I have checked your website but the sale information was for 2017.

1) Can I know when is this ticket open for sale?

2) I understand that thus ticket cannot be bought online. It can only be bought at designated JR stations. So can I reserve the Tateyama cable car boarding time when I buy the ticket in the JR stations?

3) This ticket is valid for 5 days. Is it 5 days from the day ofpurchase or from the day of use? Example if I buy ticket on 14 Apr and use it only on 17 Apr, does the 5 days start from 17 Apr?

3) The ticket cover the journey from Oaigawa to Shinano Omachi on the local bus . If I get off the bus in Omachi Onsen, stay 1 night and take the bus the next morning to Shinano Omachi, will it still cover?
Please advise. Thank you.

http://jrtateyama.com/e/

The sales period will be similar dates to last year.

Your other questions are answered looking at the website.