Hi David,
You are indeed a brave man. This is the kind of commission that would drive me crazy. Let's see... you didn't take the photos, you need to combine photos, you need to remove sun's rays, etc.
and you're under the time pressure of a suprise birthday gift. I also think both of these compositions are unworkable. (And now aren't you glad you asked for advice?
) I hope you're charging a lot for this painting.
I would reshoot the mother and children in an outdoor family pose that works better compositionally. Be prepared to take at least a hundred photos. Search through the SOG websites for some ideas of outdoor family groupings (email me privately if you want to know who I personally thinks does this very well, but I'm sure you'll have your own opinions in this regard). I might do something clever such as have a stand-in for the husband, loosely block in a "guy" shape in the painting, and present the nearly-finished composition at the husband's birthday. The stipulation will be that you'll complete him later, after the birthday. This will buy you more time and give you a much better chance at getting good resource information, as well as having the chance to paint a sketch of him from life if possible.
Before shooting any photos I recommend that you sift through all the photography advice on this Forum, especially with regard to shooting outdoors.
You may be pleasantly surprised by how well received you ideas are with your clients, especially if you become enthusiastic about the painting. Remember, many clients are really only interested in whether they look attractive (specifically, whether they look
fat). The burden of composing a wonderful painting lies on the shoulders of the artist. You have a lot of talent and I will enjoy seeing what you do with this one, David.