2- In Electrum, When I want to send a payment it doesnt let me choose to pay from what address, in Multibit Classic if I remember correctly, each bitcoin address act like a bank account balance and you could choose to pay from what balance.
For example it was like
- BTC address A (MR X paid me in past)
- BTC address B (MR Y paid me in past)
so when I am going to buy for example a cake and I dont want MR X find out about It, I could use the balance BTC address B.