I think my plan of action would be to keep looking to modify the FP, but if I couldn't get it switched to earlier we'd aim to RD it. Then, if we made it, we'd modify the FP to something else earlier in the day.
Yes, it's often repeated on here that there is no slow time at WDW anymore. But it's a Friday in January. It's not exactly prime visiting time. I would think that as long as you're at the park by rope drop (and yes, even towards the back of the rope drop line) you will be fine. It's EMH so you're only fighting on site guests with no BOG breakfast eaters in front of you and there are no FP returners to slow the line.