I seems that '5th sentence counting from the end' is not clear enough. Define better 'counting' and 'sentence' please
Count the same way as you would count from beginning. It means that last sentence is first counting from the end.
do you include the terminating dot in the sentence ?
You can read in pdf: 'The last character of the solution is a period "."'
do you include the initial space (encoded with a star) in the sentence ?
No, it is not a part of a sentence.
do you confirm that stars are separating words in the validator with all camouflage chars removed ?
You can read in PDF: 'Keep in mind that "" in the plaintext represents " ", so after deciphering simply replace every asterisk by a space.' …so it means that in solution there are no asterisks as they all have been replaced by spaces'*