Hi AmandyLyne - welcome to the world of axolotls, and the Forum!
If your water is still murky, you can check your filter; it may be full of gunk and need a cleaning (a good idea every couple, three months). To clean the filter, fill a bucket with water from the aquarium and rinse the filter media in that - that way you disturb the bacteria in the filter less than by running it under tap water.
Fake plants don't need to be quarantined (they also don't require light or specific temperatures, which is why I have long preferred them to live plants).
As you can see, water conditioners are somewhat disputed. There are some solutions you can add to an aquarium that have aloe vera and are supposed to help maintain healthy skin. So far I have never seen conclusive evidence that these help, nor has it been proven that they do or do not hurt an axolotl - so in that case I'd say it's best to leave them out.
Then there are "starter bacteria" solutions. These generally are bunk. There is one called BioSpira that apparently really contains live bacteria - it is kept in the fridge at pet shops, although also reputed to be difficult to find. This solution is only intended to help kick-start the biological filter (cycling a tank).
Dechlorinators are certainly the most commonly sold/recommended solutions. The trick here is to know whether you need a dechlorinator at all. To do so, you need to call your water company or check its website and find out if you have chlorine and/or chlormaines in your water supply. For example, here in Germany, we don't; in the US and Australia, they do. Chlorine will evaporate - if your water contains chlorine, it is enough to fill it into a bucket with a hard spray (like from a shower head) and let it stand a bit (minutes, hours, overnight...) before adding it to the tank. Chloramines, however, will not evaporate. If your water supply contains chloramines, you need a dechlorinator to remove them.
Although it seems at first to be necessary, good, and even fun to add chemicals of various sorts to your tank, many are not beneficial, some may be harmful, and all are an additional expense in the long run.
By the way, I think your axolotls are awfully cute. Look well fed, too.
-Eva