Okay, I had a request so I'll just post some sketches here. Sorry for the sloppy work, tho. :$
First attached sketch is for running 4 LEDs in an array. The specific request is to run a total of 16 LEDs and an EL sheet. So I sketched two complete LED arrays (the two vertical strings of 4 upside down triangles, which are called diodes - that's what LEDs actually are) and then I got tired of sketching and just drew three more arrays with (...) in each array to represent the LEDs and the EL sheet. See? Sloppy work...
In this first circuit you do not need resistors. Each LED is rated at between 3.3 and 3.5V. So each 4-LED array "wants" to be "fed" between (3.3 x 4 =) 13.2V and (3.5 x 4 =) 14V. You're only supplying 12V, so each LED will run slightly less bright than if you had a 14V battery. EDIT: note that for some LED types you may experience a noticeable degredation in brightness running at less than 3.3-3.5V. For this reason, your preferred choice may be the 3-LED array discussed next. I will confess that I don't know what the spec is for your EL panel, so I don't know if you might require a resistor for it or not.
In the second attached (sloppily drawn) circuit diagram I show a 3 LED array with a resistor. If you're REALLY worried about running your LEDs without enough voltage, you can step down to only running 3 LEDs in each array. Now you'll need to construct 5 arrays each containing 3 LEDs plus another array with only 1 LED, plus another array with your EL panel.
So in this second circuit you DO need resistors. Each array requires a 75 to 100 Ohm resistor. This is because the 3 LEDs in each array only "want" to be "fed" up to 3.5 x 3 = 10.5V. You have to find some way to "consume" the remaining 1.5V (or slightly more if your LEDs are rated at 3.3V) that the 12V battery is supplying, otherwise you'll burn up the LEDs. So that's why you insert the resistor in this circuit. 75 to 100 Ohms running at 20mA current will produce the needed 2.1V or 1.5V. Realistically you can simply choose 100 Ohms (a common rating) and be done with it. Note that I've assumed that each array will be running a current of 20mA. That's typical for LEDs and should be typical for the circuits that you'll be constructing here.
For the array where you only have 1 LED at 3.5V, you'll need a resistor for that array that can provide 8.5V (12V battery - 3.5V LED). So you'll need a 425 Ohm resistor (or thereabouts; anything from 400 to 500 Ohms should work well; your LEDs can run a *little* "hot"). Again, I don't know what your EL panel will require.
For those new to electronic circuits, I've uploaded a third diagram which shows how the second circuit would be wired. Note the polarity of LEDs: the longer lead from the LED is the positive lead. The peanut shaped things at the top of each array are the resistors.
PM if you have more questions. It's not difficult - it just takes a bit of experience and a few "smoked" LEDs to get the hang of things! Good thing LEDs are cheap! :lol