Text mining, Analysis and visualization of documents

I have a bunch of textual documents on Constitution. Documents vary in size from 2000-90,000 words. Need to do topic extraction from each document; From the corpus need to extract common topics, tokenize the data, tabulate and visualise n-grams of text. Find similarity and divergence between the topics, search whether an topic/sentence is present within a text. Upon successful completion, a further addition of sentiment analysis of Debates needed. Skills needed: Data Mining, NLP , expert coding in R or Python, using NLP packages, and visuzalizations.
Time needed : about 20 hours - in One month