The way you have made the connections are certainly valid and as you have shown, they work, however for other readers of the forum, there are “easier” ways to do this.
The most “obvious” way is to simply plug in the UART Serial https://www.96boards.org/product/uartserial/ mezzanine board and use a micro USB cable to your laptop. The UART Serial mezzanine card has exactly the same circuitry on board as the FTDI adapter that you connected. Of course, if you have your own mezzanine board already plugged onto the DragonBoard 410c, then this may not work for you (some mezzanine boards have a pass-through and you can plug the UART Serial card on top of them).
The second less obvious way, which works if you already have a mezzanine board on top of your DragonBoard is to use the Audio Mezzanine board https://www.96boards.org/product/audio-mezzanine/. The Audio Mezzanine board has the same FTDI circuitry as the UART Serial card, but it also has full pass through of both the low-speed and the high speed connections (you can disable the rest of the circuitry on the board by sliding the switch SW1 the OFF position). Most of the camera mezzanine board manufacturers have used this trick while debugging their designs.
Finally, you can also use the Sensors Mezzanine board https://www.96boards.org/product/sensors-mezzanine/, since this also has the same FTDI circuit on board. The Sensors Mezzanine gives you a lot of interesting features (including an Arduino) but is not stackable like the Audio Mezzanine.
Full disclosure: I am an employee of Qualcomm Canada, any opinions I have expressed in this or any other post may not reflect the opinions of my employer.