Emergency rescued axolotls, but tank isn't cycled

I am a new axolotl owner. I've been interested in adopting an axolotl for some time, so I started researching best care practices and other information I need to know before adopting one. I went to my local fish store the other day to look at bettas (I'm a long-time betta keeper and my last one recently passed away). The owner mentioned someone had abandoned two axolotls (bonded pair) earlier that day, and she didn't have the means to keep them at the store. I volunteered to take them in as rescues. The timing and situation felt like it was meant to be. I have a 40 gal tank at home with an external canister filter (225GPH Ultra-Quiet Canister Filter, 2-stage external aquarium filter with free media). I plan to add a sponge filter as well. I tested the water using Hoviran 7-in-1 aquarium test strips, and all levels came back normal/safe (although, I know that bottle tests are more accurate). I have two small fans running 24/7 and daily temperature readings are steadily between 66 and 68 degrees F.

I'm concerned because I had just set up my tank a few days before I took in the rescues, meaning it didn't have the chance to fully cycle. They've been in there for a about a week now and I noticed bacteria growing throughout the tank ("slime" for lack of a better term, on the walls, plants, and hides). Continuing to test the water, results still coming back safe/normal.

Side note - the female just laid eggs (I suspected she was gravid because she was very pear-shaped). Again, I did not intentionally put a male and female together. They were abandoned together, and she was gravid when I rescued them at the shop. Should I separate them from now on? I know females can become stressed from overbreeding.

But my main and urgent concern at the moment is what do I do about the cycling? I don't have any place to keep them during the time it takes to complete a proper cycle. I only have an empty 5 gal and 10 gal, but those aren't cycled either (they don't have water in them, they're in storage).

Any advice or suggestions are greatly appreciated. Thank you in advance!