I came here with a C317 visa, then extended it to KITAS. So, no, you don't need any onward or return tickets for that. I applied on November 18, 2022, and within 5 working days I got my C317 visa. They will give you three months to use that visa from the date they approve it. So you can enter any time you want within that 3-month limit.
The documents I provided were:
1) My passport details and picture
2) My birth certificate
3) Our marriage certificate was apostilled by my country's embassy.
4) Bank Statement showing 2000 USD
5) COVID Certificate
6) Statement Letter for Health Protocol and Insurance
I have uploaded the C317 visa, and here is what it looks like: https://ibb.co/DrwRTj1