My sons is allergic to all of those. I will reel off some ideas, but my son is 2 so Im not sure how helpful it will be.
Dinners are easy its always in 3's for each meal - vegetables, potatoes in many different forms and meat or fish.
Lunches we do brown rice pasta with tomato based pasta sauce.
Jacket potato with tuna and home made soya and egg free mayo.
Rice crackers or corn crackers with hummus.
I bake my own bread, so that with bacon.
Rice and fish with fruit after wards.
Home made wheat and egg free pizza base with tomato sauce and tuna and sweetcorn (tastes lovely, even without cheese!!)
WRT the negative results, was it a blood test or skin prick test? The test are notoriously unreliable. Only right 50% of the time.
However, I made the mistake thinking that a positive was wrong. For example, my son is anaphylactic to dairy but seemed ok on soya.
Then I noticed that he wasnt alright with soya, he just reacted differently, which was green mucousy, acidic smelling nappies and waking a LOT at night.
Reactions come in different ways.
Good luck.