I think it is wonderful that you are taking such an interest in the lighting as a director. That said be careful not to overstep your boundaries as a director because the lighting is the cinematographer's responsibility (And the specifics of the lighting is the Gaffer's responsibility). Theoretically, in terms or creating a look, it would be better to work with the cinematographer and describe the look as you described it here "upbeat" "colors that pop" etc...
I say "theoretically" because you are having trouble getting a hold of the DP and are having to start thinking about this stuff yourself. That's unfortunate. I would try to at least do a phone conversation with the DP about this stuff as soon as possible to keep him in the loop, but if you can't I totally understand why you would need to do some of this pre production planning yourself.
For fill light, you are better off using a bounce board than a lite panel because you are bouncing a strong source (the sun). A small bounce board is good for closeups, but you will need to use much larger frames for wider shots (such as 12 x12 muslin, ultra bounce, grifflon, etc). The lite panels seam to be bright enough on interiors, but they can't compete with the sun. by colors popping, I'm assuming you want a highly saturated image (please clarify because I once operated on a show where the director would want the digital image to be so overexposed that it clipped. I thought it looked horrible, but the director said "I love how the image pops." Good times
In my opinion, one of the greatest sources of saturation is the art department. Sets and wardrobe that are made with highly saturated colors will greatly help you get that image. It helps to use complementary colors (Ex: Having a man in a yellow suit against a blue background) Unless you want the entire movie to be highly saturated, you can have the previous scene and the following scene be less saturated. This contrast of saturation from scene to scene will make the scene in the middle seem more saturated.
Chimeras are great for soft light, but usually extend out fairly far out and this could be difficult if you are in extremely cramped quarters. You may want to consider bouncing the light off a bead board. If you don't have much space to cut the light with solids, you could use a piece of showcard. Bounce a light into it. Cut off the side spill by bending the card until it cuts what you need. and then use a piece of paper tape to hold the card in this folded position. A really great gaffer showed me this trick and it definitely can help when you are on a budget and in a pinch.