Twinkle bus Furano on 14 Jul - 19 Jul 2017

Twinkle Bus Furano Lavender Course
Twinkle Bus Biei Lavender Course
Have a ticket buy on this period ?
How much is it the ticket?
Where can i buy the twinkle bus ticket?
Can I buy 2 courses on 1 day trip ?

You should need to wait for a while.

In the last season, JR announced their services for Furano and Biei at Apr 28, just before the Golden Week in Japan.
https://www.jrhokkaido.co.jp/press/2016/160428-1.pdf

In 2016, there was no Twinkle bus in Furano. Instead, they run two buses, at least every day during Jul 2 - Aug 21.
1: Kanko Syuyu Bus. 3000 yen
2: Furano Kururu-Go. 1200 yen for one day, 1500 yen for two days
http://www.jrhokkaido.co.jp/travel/furano_sum2016/bus02.html

There was the Twinkle Bus Biei-Go in 2016. They run it at least every day during Jun 25 - Aug 21. They also provided Biei Gurutto Pass, but not in July.
http://www.jrhokkaido.co.jp/travel/furano_sum2016/bus03.html

So, until the end of April this year, just read the information at their page, including a special pdf for Twinkle Bus.
http://www2.jrhokkaido.co.jp/global/english/travel/

Is Twinkle bus available in May?

Not likely. Here is the full schedule for 2016.

Twinkle Bus Biei-Go:
2016.6.11-2016.6.19 Saturdays and Sundays
2016.6.25-2016.8.21 Everyday
2016.8.27-2016.9.25 Saturdays, Sundays and Holidays

http://www.jrhokkaido.co.jp/travel/furano_sum2016/bus03.html#twinkle_b...