Thanks all for comments
I have been watching their behaviour during these 8 months. Firstly, they didn't visit the water dish at all. Then, they began to go to it more often, water dish appeared dirty, cocoa fiber inside. Well, after long time by this way, I decided to reduce land area and offer them more water, with rocks where they could be attached in case they weren't able to swim. Watching them, I could see how they started to breathe being underwater, putting their heads out of water surface, and eat too, but they are used to eating with tweezers, so, they haven't been able to find food alone yet, they are trying.
I'm looking forward the moment they'll go to water again, but they still like spending time on land. I hope they don't drown, they are doing it very well.
About raising newtpoles with adults, I have other bunch growing with their parents and 1 or 2 are expected to morph during this week. Well, I don't know what to do, because I'll be travelling and my parents are going to take care of them. It's a big problem because I don't know if the recent morphs will want to be out or if they could live in the tank with no land area... >_< Of course, I would like they remain aquatic, anyway I'll prepare a tub for the new ones.
New pics, larvas-adults living together
Cheers