I believe you are correct on both accounts. The real reason why this Boston club was so awful was the extraordinarily high ERAs relative to the era.
With O'Rourke at 5.05 and the other starter at 4.00+ in an era where the league would post a 2.10 ERA (lots of unearned runs!) that would be the main cause.
But while below .200 averages were certainly common, here's a list of all the pre-1900 players with at least 70 games at catcher (Ingraham had 77, and for those just joining, a .152 average). It's only 11 players, and Ingraham would rank as the second worst starting catcher of his time.
Code:
Cnt Player BA Year Age
+----+-----------------+-----+----+---+
1 Harry Sage .149 1890 26
2 Malachi Kittridge .176 1899 29
3 Jack Boyle .183 1892 26
4 Connie Mack .187 1888 25
5 Jack Ryan .189 1898 29
6 King Kelly .189 1892 34
7 Jack Boyle .189 1887 21
8 Barney Gilligan .190 1886 30
9 George Myers .190 1886 25
10 Morgan Murphy .197 1892 25
11 Barney Gilligan .198 1883 27
He'd also rank in the top 10 worst batting averages for any player qualifying for a batting title prior to 1900.
Code:
Cnt Player BA Year Age
+----+-----------------+-----+----+---+
1 Will White .136 1879 24
2 Jack Burdock .142 1888 36
3 Will White .142 1878 23
4 Charley Bassett .144 1885 22
5 Henry Easterday .149 1890 25
6 Harry Sage .149 1890 26
7 Redleg Snyder .151 1876 21
8 Frank Barrows .151 1871 26
9 Sam Crane .153 1886 32
10 Al Nichols .153 1875 23