If you mean dilemma as in 'a problem with no acceptable solutions' then yes, you are spelling it correctly.
No, the correct spelling is dilemma (a difficult situation).
Yes it is spelled correctly
You have spelled 'still' correctly.
Yes, engineer is spelled correctly in your question.
Flattest is spelled correctly. The others are spelled: silliest, biggest and sweetest.
Yes, surprisingly is spelled with an S. Surprisingly is how you spell it. You spelled it correctly.
You've spelled it correctly.
Convenience (easy access or availability) is correctly spelled.
It should be foreign.
yes, that is correct.
No, "infrachrondal" is not spelled correctly. The correct spelling is "infrachondral."
Correctly: How did Elise spell? She spelled correctly.