I would say that 2 pork chops is likely to weigh more than 100g, but I could be wrong! I would also say even 100g of pork chop would be a bit higher in calories than we're allowed (roughly about 200ish cals). I know pork isn't on the S&S sheet but people do have things that aren't on the list and have been ok, it's up to you if you want to 'modify' the plan though. For example people have been having 2 eggs for their protein meal even though it's not on the sheet. If you are worried just drop S&S an email and I'm sure they'll be able to advise. Pork in itself should be ok if you have the right amount to not go over your calories for your 4th pack. Plain pork chops don't contain carbs, just like chicken, turkey etc so you wont be knocked out of ketosis.
I can't comment on the fish as I rarely eat it.
Chicken fillets can vary in size, so it can depend really. But if you don't have scales and can't weigh then I would say that you would be ok with 1 chicken breast fillet. If it actually weighs a bit more than 100g the calories might be a bit higher but not much and seeing as you don't have the veg will leave you with a few spare anyway.