Startech pm1115p2

No it is not possible to connect to a BOB as it has the Centronics 36 pin port, not the DB25 one, and making an adapter (probably no way to find it) would probably require some junk yard scavenging to find a female Centronics port.
All that is probably in vein as it might not work with LinuxCNC at all.
And now the hard answer:
Go buy a Mesa 7i92T, it is the same price, has two ports with 34 IO all can be inputs or outputs, and can do much, much faster step rates and read fast encoders.

You are welcomed, always.
Just to be clear, i have nothing to do with Mesa, i did my first retrofit with their boards a long time ago, and many more since then as i absolutely must have reliability, and those do. Also, any price you see for Mesa stuff, i have to pay at least twice that to get it here, and i pay it gladly.
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For the price of the adapter you linked with big chances it will not work, you can also get a used PC with parallel port that works perfectly well with LinuxCNC, the port works, PC might still have issues with latency, but the big Dell Optiplex 980 have worked fine for me.
But if you can stretch a bit, get the 7i96S, makes wiring much easier.

Yes it is, 8 data pins, 4 control pins and 5 status pins, if i am not mistaken.