Hey Dustin I’ll offer my thoughts.
I’ve poured a lot of concrete in the last twelve months, and here’s what I’ve learned from concrete guys, my contractor, and my own obersvations.
Concrete is heavy, heavier than water. I was pouring concrete in three foot tall form tubes, with about two of those feet in the ground and a foot above ground. I accidentally mixed one batch with too much water. It was soupy, like really soupy. I poured it in, and in real time over the course of a few minutes, I watched the concrete ingredients (what they call “heavies” in the construction world) settle, leaving a puddle of water about an inch and a half deep at the top of my form tube. I dumped more wet concrete in, which displaced the water, resulting in a cylinder full of concrete. Having witnessed this, I like to think that if you were to pour a footing in a single pour, the heavies are going to occupy all the space in the hole and any ground water will be held back by the greater in mass & density concrete. If there is standing water in the hole, I suspect that as concrete is poured in, it will be displaced and come up and out of the hole in the ground.
You mentioned you’re up in Pennsylvania, and I imagine things are still cold. If I may offer a piece of advice, consider using the fast-setting type of concrete mix, and/or use hot water when mixing the concrete. I was chatting with my concrete guy and he said calcium carbonate is added to wet concrete at temperatures below 70 degrees to generate heat to help it set. The colder it is, the more is added, and on really hot days in the sun, retardants are added to slow the concrete setting so it can be worked. Concrete doesn't dry, it cures. The chemical reactions that make it harden vary in speed depending upon how cold or hot it is. Also, avoid letting fresh concrete that is 24-48 hours old freeze. The water molecules haven't had enough time to bond with the concrete mix, it can freeze and expand and structurally weak concrete or crumbling failed concrete can be the result.
I’m no concrete professional but it’s a few things I’ve learned along the way. I hope this helps you if you choose to mix more concrete for your footings. Best wishes!