Glad to here the frogbit is doing better. Usually because duckweed just grows and grows I don't care if I suck some up. If you don't want to lose so many, at least if you use a bucket to change the water, is just scoop out all the plants that got sucked up.
I would put the plants in another bucket while you do the 100%s
That was a problem when I first got my frogbit as well, it may just be adjusting to the different water. You should notice growth in it in a week or so, maybe longer as it is a much slower grower than the other two.
1-2 weeks is fine. Really the only thing you are quarantining for is bugs, snails, and diseases, but diseases will go away in tap water. I personally never bother to quarantine, but I do if it obviously has signs of algae or snails. I try and stay away from those plants when buying in the first place.
The water lettuce is fuzzy and is rather dull in color. I gave you a lot more of it than the frogbit.
Frogbit is the one that was in the same bag as the guppy grass. It is very vibrant in color and is smooth upon touch. These sol also grow some pretty impressive roots. I had roots that almost went to the bottom of my 15 gallon, which is about a foot high.
I would suggest quarantinimg any plant. I feed live foods a couple of times, so you don't want any kind of living thing with the plants besides the plants. Safer that way anyways.
Put the plants in regular tap, don't add dechlorinator, it will kill all the bacteria that isn't dead yet. Let them have sunlight and make sure they are all in the water, they get very fragile when there is not a whole lot of water so be careful with them. Some will probably be damaged as some ar pretty sang big.