The only difference between a smart contract address and a "normal" address is that the smart contract address contains (the smart contract) code. Other than that, they work the same.
If there is, for example, a contract on 0xfoo and by random chance you get the private key for this address, you can transfer Ether and tokens from this address like any other ...
An Ethereum address of an Externally Owned Acccount (EOA) does not differ in the format from an Contract Account (CA). You can lookup how the address of a CA is created in this (clickme) great post. It is not impossible to find a collision. In my opinion, it is even highly propable that collisions between EOA and CA accounts do exist. I am not sure though if ...
Ethereum uses ECDSA public key recovery algorithm https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm#Public_Key_Recovery to verify signatures.
The recovery algorithm allows multiple possible solutions.
I recommend checking out the book "Mastering Bitcoin", specifically Chapter 5to learn more about wallets:
The word "wallet" is used to describe a few different things in
At a high level, a wallet is an application that serves as the primary
user interface. The wallet controls access to a user’s money, managing
keys and addresses, ...
The term "wallet" can be used in many different ways, but most commonly it is used to refer to interface or application to manage an account or address, such as MyCrypto or MetaMask. With a wallet, you can generate a private key (or mnemonic phrase, keystore file, etc.), and use the software to send transactions and sign messages.
Cryptocurrency is basically a form of cashless money. It does not have to be stored. Instead, balances of all accounts have to be recorded somewhere and all participants need to agree on what current balances are.
Ethereum uses sophisticated cryptography algorithms to allow honest participants to agree on current balances without knowing nor trusting each ...
Transactions from an exchange are usually sent from a "hot wallet", basically a wallet that is managed by the exchange. Most of the time exchanges pay for the gas, so you don't need any ETH in the exchange to withdraw tokens.
In the case of a decentralised exchange (DEX), you do need some ETH, since those kinds of exchanges are based on a smart contract.