It is out doors so that helps minimize potential problems but the falls popularity means that there likely will be people around you.

I grew up three blocks from this park and it holds the dearest memories for me. It's a wonderful family destination. The upper falls area has picnic areas and a great garden celebrating Longfellow's poem "Hiawatha" and there's an iconic statue of Hiawatha carrying Minnehaha across the water. If you can navigate the stairs to the lower falls you can hike a very short distance to "the deer pen" where there's an open area for picnicking. There's also an enlarged area of Minnehaha Creek where families can go wading. And for slightly older kids you can hike a mile along the creek all the way to the Mississippi River. You do need to pay to park if you want to be close, but the entire park is free. Go and enjoy!!

Officially no, though people do go behind there. Seeping groundwater can make footing very treacherous.

Yes...picnic tables and grills in the park.

check the light rail route, I do believe there is a stop near the park.

You can rent various forms of pedal power suitable for 1-4 people. We rented a 4 person vehicle which was difficult to get up hills so someone had to get out to push the vehicle. Even that ended up being fun. It is a lovely walk or walk down the stairs to the bottom of the falls.

For convenience, there is a Nice Ride self serve bike station at the site, but I find them very heavy and you have to recheck them at a station periodically. See their website. For a better bike you can search for bike shops in the vicinity.

Try the Sea Salt Restaurant which is attached to the pavilion and has outdoor dining overlooking the park.