It is экскурсия.
Note that -ия-endings nouns (e.g., химия, Мария, фотография) have a different Dative/Prepositional ending than you might expect:
- На фотографии моя мама (Prepositional).
- Скажи это Марии (Dative).
- Я ничего не знаю о химии (Prepositional).
Usual а/я-nouns have a е there, not an и.
немного туристов means "a few tourists". "Some tourists" is wrong because there is no amount specified in this particular sentence - it is just stating "tourists", without quantity. If you want to say "some tourists" it is better rendered as несколько туристов (if you mean a small number) or некоторые туристы (if you mean a specific set of tourists, ie, some tourists in a group are talking about the tour, others are not.)
Yes, it makes no sense. You cannot expect people to accurately reproduce quickly-spoken foreign words. It's just the nature of human perception. We repeat what we think we hear, not what we actually hear, and often what we hear is what we're expecting to hear, or what we're used to hearing. The mind can play tricks, and transform foreign sounds into English approximations, so that the end result is recognizable by neither language.