You might want to try shortvort.com - it is a website full of very nice, small divrei Torah covering the full gamut of Jewish thought.
You can submit a 'vort' here where it also lists the site's policy.
You can access it all on the Otzar site here
You can also access it for free on the National Library of Israel here.
In addition, some kehillos (congregations) include the special Selichos for Children's Illnesses as part of the service which can be accessed free from Artscroll here.
Accordance, which is available for purchase online (there's also a free version that gives you some text access, but I don't recall how much), allows these kinds of searches. For example, in the picture below, I looked for all verbs in Miketz and sorted them by hits by root (you can see the frequency in percentage, or make a pie chart, ...). You can then see ...
The closest thing I have seen to what you are describing is Alhatorah's concordance graph. It graphs frequency of roots across different books in Tanach (although not parashiot, as far as I can tell). Also, their concordance is the best one that I am aware of online - try it out with different roots, forms, and play around with the settings to learn more.
To get a basic understanding of the Kabbalistic ideas discussed in Sifrei Chassidus, שפתי חן is a fantastic Sefer that I have found tremendously beneficial for my learning of Chassidus, and it has also given a good foundation to build on for Kabbalah in general. There are shiurim available from Rabbi Yoni Levin through the YU Torah website, but the shiur ...