It shows up as wheelchair accessible. However, it also says gravel path... is is truly packed gravel so a wheelchair can be pushed on it? Or is it regular gravel that a wheelchair sinks into and gets stuck.

It's mostly packed gravel but there are some sandy areas where narrower tires can sink in. I ride my gravel bike around the pond and my tires are 45mm. Road bike tires wouldn't work there.

Yes

A wide wheeled electric wheelchair could do it. There are a couple spots of loose sand though.

It's pretty solid I don't think you'd have a hard time pushing a wheelchair the water is real low though but there are a lot of birds to see

It's pretty packed but there are some areas where it is disturbed.