1) Some poskim allow the color of salmon to replace the normal simanim (scales), but some don’t.
2) I can’t understand why bishul akum isn’t a problem, as well as the spices (although there are ways around the knife problem).
3) The only salad which would not be problematic would, besides for not having anything sharp, would not have vegetables likely to have bugs (or dressing). Also, again, the knife is a problem for any vegetables, unless you can ascertain that it was properly cleaned.
4) Maris ayin might not apply according to some poskim, because it’s become common to meet business associates in a non-kosher restaurant. Eating something would make the problem worse, since the majority of foods (even salads) served are not kosher.