"Did the Bible Students in the days of Pastor Russell believe he was the F&DS, yes."
I will say that this was the prevailing view. From Russell's standpoint, he never assumed any authority to tell anyone they had to believe such or to reject such an idea. From the standpoint of Russell and the Watch Tower Society as it existed while he was alive, it was an individual matter, and thus while many Bible Students did believe he was "the faithful and wise servant," not all the Bible Students agreed with this. The same is still true among the Bible Students today.
To me, the ideas presented about the faithful and wise servant being alleged as being identified as a certain person, or a certain group of persons, is not what Jesus was referring to. There is nothing in his parable that says that he was speaking of appointing a certain person or group in the end of the age to who is supposed to be some sole channel of dispensing truth. My own study concerning the four servants may be found at:
https://prophecy-rlbible.blogspot.com/2016/12/4servants.html