Hi possible neighbor! *waves*
Let me take a crack at these questions...
About the strawberries: smart idea to dedicate a bed to them! Yes, I would do 8 plants in a 2x4 bed, just keep the runners somewhat in check and be sure to mulch them nicely when winter is on the way--one favorite mulch is straw or salt hay.

Before I forget, I wanted to let you know about this really fun garden planning thingy on the Gardener's Supply website. http://www.gardeners.com/Kitchen-Garden-Planner/kgp_home,default,pg.html
It's basically set up for SFG already, just put in your bed dimensions, drag and drop the desired veggie to a square, and read the planting notes they give. Loads of fun to use and I find it very informative in some ways. It's also nice to get a visual as to what your filled beds are going to look like. It also auto-fills the quantity in each square, which is fun!

I personally like to plant tomatoes in the same big box with peppers, carrots and lettuce, and maybe trellis the beans/cukes in the same box as well--for instance, run a trellis along the entire 4' north side of the box and do tomato/bean/cuke/tomato on the trellis and repeat in the other 4x4. I plant my peppers in front of a tomato plant, generally, but they could go just as well in front of the cukes or beans. They may need support late in the season though (mine rarely do for some reason) so keep that in mind when siting them. I personally think pole beans are much better bet for production, BTW--bush beans usually (always?) ripen all at once, while pole beans are pick and come again crops. Carrots and lettuces I stick in the front of that same box, since they're small and quick to grow, plus I like to have a full salad bowl in one box whenever possible.

Keeping in mind that leeks have a very long growing season and can store in-ground very nicely through much of the winter *and* they're expensive to buy, I personally would plant loads of them, maybe even the entire 2x4 box. Or split that box between chard and leeks, assuming there's no negative companion action? I don't know, haven't ever grown the two together.

Have never grown brussels sprouts either, but I believe they are quite a large plant? Maybe switch out one set of bean plants for brussels sprouts in the back of that box?

You could sure incorporate your cilantro plants into a "salad bowl" square if you wanted, though I would just as soon do a huge planter or more than one and just fill it to the brim with my herbs. I usually don't waste space in a SFG on herbs unless I have way more space than I need that year (which I will in my new garden this year, it looks like).

Hope this is a good helpful start!

Hi, this is my best shot at doing what your looking for. You could have shade issues if your garden is not orientaed this way.