What I don't like about exercises that put a bar on my shoulders for a long time is that it starts to cut the circulation to my arms... But with the dumbbells there isn't that pressure and you can go longer - I do 4 x 50 steps (25 steps to the end of the hall, turn around, back).
You can also do reverse lunges (stay in the same place but step backwards) or regular lunges in place. I just find the bar limits the duration of 1 "set".
RE: bodyfat-- its just a number. But it is a ratio of your bodyfat to lean muscle mass - I don't think you are "fat"-- if you continue to increase your muscle mass, that ratio will drop. The different measures also help show you where your body tends to hold its bodyfat and / or water. I tend to hold a lot of fat & water, particularly water in my triceps & my calves. (In addition to the usualy waist & thighs) -- so take the measures for what they are worth - they give you some insight into how your body "works". And also shows you where you tend to hold the fat / water, where you would drop bodyfat the fastest or where you are increasign your muscle mass the fastest. Its sort of interesting, but still - it is just a number. What ultimately matters is how you feel, how you look and the changes over time. Its always a "journey" to a goal where the goal is where you always need to focus if you aren't happy with where you are now because where you are now is just a point that you are passing through on your way to your goal!
BTW I had to put your cute little kitty in my signature! TOOO CUTE!