Complicating cycling Q. *sigh*

[FishTales]

I have an older established 29g. I think my tank went through a mini cycle recently (we left to much food in the tank at some point, stupid me). I had 6 fry that all died sadly and 2 of our 4 original mollies died. I think the culprit may have been columnaris. The male also developed puffy patches (this is very different looking than the common ich). One on his back below his dorsal and puffy stuff around his mouth that caused it to slightly protrude. He was hanging around the top gasping for air. I had set up a 10g tank a week ago. I managed to have enough gravel in the big tank to gravel the 10g. I 'primed' my filter by placing it in the large tanks filtration prior to installing it. Also happened to have bacteria supplement. The readings on the 10 gallon I set up are already normal? Idk if I just happened to catch it before a peak or... Anyhow, I put the sick fishy in there. My LFS doesn't seem to carry the proper antibiotics. I had a 2 year old bottle of coppersafe though. Knowing it is bad stuff for fish, I looked it up and it had very mixed feedback saying its not ideal for columnaris but may work. I did it anyways but at half the dose. I also very slowly raised the PH with Baking soda. Tell me if that was dumb. Strangely enough all the slimy fungi stuff on him was gone by morning. His mouth looks 70% better. The problem is, I have a swordtail about to pop and THIS was supposed to be a fry tank!! Should I put him back with the masses? It really can't cycle in one week can it? All perameters are still normal. I saw this on youtube and made it as a temporary back-up until I figure it out: (enter DIY Breeding/Isolation Net/ Box on youtube) Will syphon the fry in after birth with a turkey baster lol
Anyone have good suggestion? If amonia or nitrite pops back up can I use Prime with fry or to risky? Can I bring the coppersafe down to at tolerable level? Sorry for the book. My daughter is really excited about the swordtail fry and I'd hate to kill her dreams... literally.