This post is intended specifically for those having issues with the MFT correctly identifying your X98 when you connect it to the USB bus.
I was reading the MFT User guide (a PDF stored within the MFT install folder) and I came across this page:
Note the section and words I have highlighted.

This intrigued me, since all the instructions I have ever seen regarding MFT include the installation of the iSoC drivers and mention that MFT will not run without them.
However, I decided to test the theory and I can confirm that, yes, the X98 in DnX mode is identified correctly and MFT is functioning properly with the iSoC drivers uninstalled. I even went so far as to run a few tests and by installing the iSoC drivers,
I was actually able to get my system into a state where:
Device Manager appeared to correctly detect and identify my X98 in DnX mode
MFT was NOT detecting my X98 at all and therefore was not flashing the X98
I was then able to fix the problem by uninstalling the iSoC drivers and re-installing the Intel Android drivers.
I have already updated my Install and configure MFT tutorial here:
Install and Configure the Intel Manufacturing Flash Tool on a Windows Host PC
However, for anyone who currently is having MFT problems, I recommend you try the following:
Go to Control Panel-> Programs and Features , find the Intel iSoC drivers and uninstall them.
Then re-install the Intel Android drivers ver 1.10.0,
The procedure for reinstalling the android drivers is here:
Install the latest Intel adb drivers for your Teclast X98 Air device
At that point, give MFT another go and see if it works for you.