Folks from other parts of the country might not quite understand our Michigan topography. OP's area is surely kinda flat, overall. Maybe some mounds of sandy hills here and there in the region. Our rivers tend to meander back and forth in slightly lower plains/channels, with bends back and forth that can create fingers of land in between. Since the river normally stays down in its channel, the fingers will be dry-ish for 80-90% of the year, typically only flooding during spring snow melt (ground still frozen, so a late winter rain can raise the rivers FAST) or extended wet periods like we are having now. If this was my land, I would also want to improve these acres and make them usable since they would be dry enough for activities and driving on for most of the year. I would want to grab logs for firewood, make trails for hiking and viewing the river, etc. I don't know about clearing ALL of it out, but that's just me. A good hearty (native) grass could get established on the lowlands and withstand the occasional prolonged flooding events. Basic cleanup after big flooding events would be a normal routine.
My take: don't clear all of it - 7 acres is pretty huge after all. Start with trails and a few open areas. Establish grass in the late spring when the long term forecast looks damp, but not flooded (I know, hard to gauge).
EDIT: I forgot this was about what tractor to buy, haha. Really, Brand shouldn't matter. I would aim for 30-40 BHP and 2800-3500 lbs bare tractor weight. FOrget the gear trans, HST barely robs any power and its SOOOoo much more convenient. Turf tires. Ask your dealers about oversize turf tires to prevent bogging as bad in the mud. Keep 4WD on whenever conditions are wet and also learn to ride the diff lock if it's real sketchy. And simply stay out of there when its under water! :laughing: