It's hard to understand what you are really asking, but... I'll give you a shot at an answer. If I don't hit the mark, reply back with more info!

Can you wire this stuff the way you've described? Yes. Is it a good idea? Probably not.

It would be MUCH better to use the headlights (power going to them when turned on) as a trigger for a relay that then powers the LED lights/strips you want to add. That way, the only extra power draw you are putting on the headlight circuit is the relay (~1/10A). The power that goes to the LEDs comes from the battery, not the headlight circuit (and that fuse, possibly blowing it). You can then add your own switch to the new circuit so that you have the option of turning the LEDs on/off. That is, they won't ALWAYS be on when your headlights are on. Sure you could do this any way you wire it, but by using a relay, it is much safer, doesn't put any (realistic) draw on the circuit designed to power the headlights alone and you can control it at will, if you choose to wire it that way.

Hope this helps.

-G