The thing with themes is that although they use most if not all of the code that makes Moodle work, they add to it too, in the form of extras to make things more appealing with some settings, layouts, etc. So most of the look will need to come from yourselves, what YOU want, what is best for your students. In other words make a theme work the way you want it to.
Generally if you download a theme you like, with a bit of luck the author of the theme will maintain it as and when needed, or fix bugs that people report. On the other hand it may not be updated as quickly as one would like and may actually need crowd funding to update/improve before you get a new version. The latter is to be expected as this kind of theme is one of the most popular and the author needs to make a living.
If you are getting a company to set Moodle up for you then you may as well go to a Moodle Partner and pay them to make a theme to your specifications.
I learnt how to make a Moodle theme from scratch, and have learned quite a lot about Moodle and Moodle Themes over the last decade. Time is the thing with themes, you can be working on one for weeks on end, tweaking it, fixing bugs, which can in some case be therapeutic...on the other hand it can be totally frustrating if things go wrong. So as well as time you also need lots of patience.
Well that is my take on it.
Hope it helps?