Yilan Park, today’s Yilan Zhongshan park. That lake is no where to be found to day. Don’t think the obelisk is there either.
There was a Jinja, but was moved to today’s Yuanshan park.
The only thing still left standing from the Japanese era is this:
Sacrificial head offering memorial, made by the Japanese to honor those ethnic Hans that lost their heads at the hands of local Aboriginals. The memorial of course glossed over the fact that the Qing government committed ethnic cleansing of the local Kavalan and Sakizayas, executing the leaders and their wives by cutting off a piece of their flesh at a time until they die.
Some old Yilan photos can also be found here:
https://www.douban.com/photos/album/84475266/