Hi,
using the Tika Parser node is the better option to read PDF files. For plain text files youc an also use the Text File Parser.
Named entity recognition can be done by NER tagger nodes. The textprocessing extension e.g. bundles some of the Stanford NER tagger models. Relationships can not be extracted with a dedicated tagger node. You would need to do this by creating your own workflow. E.g. you could extract all NER in a sentence and the verb in the sentence. Parts of speech can be tagged using the Stanford Tagger node.
I hope this helps.
Cheers, Kilian