If chakra is converted into life than it isn't chakra, it's life. That's like saying if I convert and mp4 to an mp3, its still an mp3, but it isnt, its life. Mokuton's origin is chakra converted life but after its been converted there is no chakra flowing through it.
Since when did Preta let you choose what you absorb? You absorb what the barrier is touching and we know the barrier covers all around you, the last part of your sentence is an assumption.
It dosent work that way,if there no chakra flowing through hashi's trees,the they would be no different from normal trees,hence a tbb would go through it easily,or a susanoo sword slash. When chakra is converted,it changes it's nature,from pure chakra to something else,but it is still made up of that chakra,it dosent matter what form it takes. The trees created,are made completely from the chakra,converted into life from hashirama,hence their very existence is made from hashirama's chakra,when onoki creates a rock golem from his mouth,the golem breaks apart when beaten,the golem posseses life too,but can be absorbed,why?,cuz it got it's roots from pure chakra,and is a ninjutsu.
If you created an mp4 from an mp3,and the mp3 is pure chakra,then it will be absorbed,because it's toots were from the pure chakra,but if you saw and mp3,and using your chakra,changed it to an mp4,then the chakra inside the mp4 which you put will be absorbed,but since the mp4 wasnt made by your pure chakra,or didnt find it's roots from your chakra,it will not be absorbed. Moukton finds it's roots from pure chakra,and is a ninjutsu,hence is absorbed,howvwe,if hashi sees a normal tree he didnt make,ad uses his chakar to make it attack,then the chakta,not the tree would be absorbed.
Preta allows you to choose what ou want,you are the one absorbing in the first place,you can choose what you want to absorb,he orb around you,just allows you to absorb from everywhere,not that you automatically absorb everything around you. You are the one that would decide what you want to absorb. Also,the barrier dosent really cver all around you if you dont want it to,see when preta absorbed j-man's rasengan and gaemon,the orb was at his hands.
