Problem solved! The solution? Fairly simple. I just needed to upgrade my version of Debian from Jessie 8 to Stretch 9! That was it. Once I upgraded to the new version, the android tablet was recognized instantly! Thank you all for your many helpful suggestions and the time you took to respond to my queries. I truly appreciate your time and effort! Best to everyone for the Christmas season!

Good to hear! I guess the model was just too recent to be in the device database on Jessie 8.

Oh well, Stretch 9 is a pretty recent release, for now. It will get a bit long in the tooth by the time Debian 10 is released...that's how it goes with Debian Stable. If this gets to be a problem for you, consider doing a Debian Sid install (or even multi-boot it, so you only boot into Sid as necessary).

I've no idea what that means. What is Debian Sid (versus Stable)? I just downloaded the new version and it presented no problems whatsoever. The download took awhile to complete but not more than a few hours. Thanks!

this is a serious problem.
as a debian user, you are expected to be able to navigate their website and wiki and find information for yourself.
debian's release cycle is a very basic and important piece of information.
https://www.debian.org/releases/
https://wiki.debian.org/
if all that is beyond you, consider using ubuntu instead.

Speaking as a long time Debian user, I'll freely admit that I did NOT learn about Debian just by navigating around their website and wiki. I learned most about it first from web forums like this and LinuxNewbie (now called JustLinux).

Basically, Debian is unique among linux distributions in the way it fundamentally has three actively maintained releases - Stable (stretch for now), Testing (buster for now), and Unstable (sid always). Each of these three are essentially working distributions, but the purpose and focus is different:

Stable - This is an official release. "Stable" does not refer to system "stability", but rather software version stability. Once software is released into the Stable repository, the version is frozen unless there is a compelling reason to upgrade it. Otherwise, the only updates are security updates and maybe some bug fixes.

The bottom line with Stable is that when it's released, the software versions are pretty current. As time goes on, though, the versions get older and older and Debian Stable essentially feels stale compared to other linux distributions.

Testing - This is fundamentally for testing software which will be in the next Stable. It's more current, but I'm not sure there's a good reason to use Testing unless you are interested in participating in the Debian process of bug reports and helping identify problems etc. Well, it could be good if you want to jump to the next version of Debian a little bit early. For example, if you dist-upgrade to buster, you'll naturally already be on the next Debian Stable when it's released.

Unstable (a.k.a. sid) - This is generally current versions of software. If the software in Debian Stable is not satisfactory, try doing a dist-upgrade to sid.

Now, you could have done a dist-upgrade from Debian 8 (Jessie) to Debian 9 (Stretch). I did a dist-upgrade of my Jessie machines to Stretch, and it was pretty smooth. This is one place where Debian really shines compared to other linux distributions. You don't need to do a clean reinstall to upgrade from one Debian Stable to the next.

As for Ubuntu - I think the confusing *buntus and how they handle different desktop environments etc make Ubuntu no more or less confusing than Debian.