Can I play a character card onto the front line?

Can I play an additional card onto a line that already has four cards on it?

Can I use an event card when both my front line and my energy line have the maximum number of cards they can hold on them (four each)?

(When the energy line is full.)
If I move a card from my energy line into my removal area in order to play a card from my hand onto my energy line, can I still count energy generation on the card being moved into my removal area?

Do resting cards generate energy?

When I use a card, does it consume generated energy?

Do I have to fulfill required energy even after a card is used?

Please explain what order the following actions are performed in: checking if required energy is fulfilled, paying action points, and performing the card's abilities.

Does all of my required energy have to be fulfilled by the matching color of energy generation?

Can I also activate [Activate: Main] abilities during my attack phase or my opponent's turn?

Does a card have to be active in order for me to activate its [Activate: Main] ability?

When checking BP, do I reference the base BP value printed on the card or the BP value after cards' abilities have changed it?