Those are safe to eat but I wouldn't eat them everyday, should keep some variety in your diet.

i dont have much idea.

but canned stuff cant be the best option in general.

wild salmon is good.its got good omega 3 fA.

I have fish about 5-6 times a week(sometimes swap it with home made simple chicken soup like curry with turmeric).i mostly have common carp(pona of different sizes),rohu, katla, boal(wallago),Giant eyed p.d. river-catfish(called aar here),Puntio barb(punti here), tengra(am not sure what its called world wide), Mozambique tilapia(telapia here) , or parshe(no idea whats its called in english.sorry) we dont really get salmon or tuna here.its not very common in local markets that is.