I agree that DL does not appear to understand the English future tense. "I shall" should be allowed as it is the grammatically correct form of the unemphatic future of the first person singular of the verb to be. "I will" is the emphatic form so should not be the only version marked correct.
Yes. Technically, "prendere" is "to take" and "portare" is "to bring". However, prendere always means you are taking/bringing/carrying something AWAY from someplace, whereas "portare" means you are taking/bringing/carrying something TO someplace. In English, we can use these verbs to mean either "prendere" or "portare", differentiating the meaning ONLY by the preposition "to" or "from" The same prepositions would apply in Italian.
"I take/bring my sister TO the party" = "Porto mia sorella alla festa".
"I take/bring/pick up my sister FROM the party" = "Prendo mia sorella dalla festa."
Hope that helps. :-)