By plugging the port in a single 10 inch sub box, would this affect the bass at all?
Yes covering the port or sealing it would cause a big difference. Depending on how you are going to go about 'plugging' the port...Also this would change the sound dramatically. You will most definitely lose some bass response. But if the box is tuned for that specific 10" kicker and you sealed the port on a properly tuned/built box, you will change that tuning. Plus as most ported speakers don't have internal sound absorption to stop standing waves and ringing the sealed box will blur the sound of the woofer with multiple reflections imposing on the woofer cone further compromising the sound.
Yes. Emphasized bass from the tuned port would be squelched.
WHY would you do that?? The engineers designed it so it produces the best bass. Leave it ALONE
It would perform like a sealed enclosure or infinite baffle if it’s a big box, and you will lose output and power handling. I wouldn’t recommend it, it’s better to build or have a box built specific to spec and music preference.