3. PROBLEM 1: I tried to recover (back up) a wallet from green wallet (Android) in wasabi wallet (pc) ~
I admit that I have never used Blockstream Green wallet (if that is what you mean), but if I understood their help pages correctly, their wallet uses special Multisig Shield protection so it is impossible to recover the same wallet with a different software.
Take a look at this:
Although Blockstream Green uses industry standards for recovery phrase generation, wallets created in Blockstream Green using Multisig Shield cannot be restored on other wallet software. This is due to the unique multisig security model used for Multisig Shield wallets.
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Note: If you enter your recovery phrase from a Multisig Shield wallet into a different wallet app that supports BIP39, the recovery phrase may be accepted by the app, but it will generate an empty single-signature wallet. Any transactions sent from or received to this wallet will be completely separate from your Blockstream Green wallet.
https://help.blockstream.com/hc/en-us/articles/900001550443-What-standard-does-Blockstream-Green-use-for-its-recovery-phrase-If i understood it well, with the 12 seeds +- the passphrase i could recover any wallet, even if i lost the computer or the smartphone i had the wallet.
Theoretically yes, but you have to first check if the software in which you generate the wallet uses the standard way of deriving key pairs from a 12/24 word seed phrase (BIP39). BIP39 is the most common standard used for seed phrases but some wallets use their own standards or industry standard derivatives.
You can find some useful information here:
https://walletsrecovery.org/I WANT TO TRY EVERYTHING IN THE TESTNET before trying in the real btc chain...
Remember that im new!
That is a good decision, and do not be shy about asking questions - we were all new once.