These trades are definitely interesting. I'm always a proponent of making a move to get who you want, no matter if people think you're "overpaying". An "overpayment" now may be a bargain in the future.
With that said, I think both trades have some interesting aspects.
-SF gives up two additional firsts in 2021 and 2022. They are in a division that any of those teams can win. I can see them finish anywhere from first through fourth in the NFC West. That could be a massive come up for the Dolphins.
-The Dolphins giving up that first rounder next year could end up great for the Eagles. The Dolphins could, and I believe will, finish third in the AFC East. Could end up being a great pick for the Eagles.