In my experience with my other open sourced stuff on Github, others fixing stuff is very rare. Having issues enabled quickly turns into users demanding fixes and no amount of asking for others to chime in aiding with pull requests actually result in pull requests.
IIRC most pull requests come either out of the blue for something new no one has requested before, or they don't come at all until I explicitly say "I'm not going to fix this" and close the issue.
I've had several bugs fixed in quite a few of my open source projects. Even bugs I've posted on my own projects. And they have only a fraction of the attention yours does.
Why not open the issues up and see if it works out? If anything, you can close them if it's becoming a burden.
In any case, thanks for open-sourcing this project.
IIRC most pull requests come either out of the blue for something new no one has requested before, or they don't come at all until I explicitly say "I'm not going to fix this" and close the issue.