"Does anyone know if Colby lake is a good place to camp?"
Colby Lake is a good place to camp. It is hard to say what conditions will be like if there is snow on the pass, but if it is snow free it is no big deal, IF you stay on route, which I did not find difficult when I crossed it. If you get into terrain where you encounter 6 foot boulders and a lot of exposure, you are off route, pure and simple. Back off and try again from where you lost the trail until you find the correct spot to cross the pass. It is, after all, a trail. If there is snow on the pass, it would be wise to make your crossing in the afternoon, when the snow has softened up a bit. That will give you the best chance of a safe, stress free crossing. An ice ax and spikes are a good idea going in early, even in a low snow year, so I think you are wise to be taking them.
Finally, if all else fails, it is probably a good idea to have a contingency plan for an alternate route, should you have to retreat, taking into consideration your time constraints, food supply, etc. You will be more than halfway thru your trip by the time you get to Colby Pass, and may not have the time/food to retrace your original route. The shortest routes back to Roads End, over Milly's/Lucy's/Harrison Passes, are all off trail and involve a north facing slope, which will likely prove even more difficult than Colby Pass. That would leave Forester Pass and a straight shot down Bubbs Creek as your most likely route to get back to your car. You might consider taking enough food to support that, and let your family know that you might be a day or so late. My 2 cents.