저는 김동완과 신화를 진짜 진짜 진짜 좋아해요!!!!!. you can say this way. when you use more than one object in the sentence, you can use the object particle 을 or 를 only one time at the end of series of objects. you can use 및 instead of 과 in this case. but 및 sounds like a book word.

랑 or 이랑 is better when you speak. 랑 is used for the noun or object ending with the vowel, 이랑 is used for the noun or object ending with the final consonant. 전 사과랑 배를 좋아해요. I like apples and pears. 전 꿀이랑 과일을 좋아해요. I like honey and fruits. 과 or 와 is used in books or documentaries. If we say 과 or 와, that's when we speak in front of groups of people.

your korean sentence is almost perfect....^^ 저는 김동완"과" 신화를 진짜 진짜 진짜 좋아해요... or 저는 신화"와" 김동완을 진짜 진짜 진짜 좋아해요... in this sentence, "과", "와" is same with "and" we can choose one of them through pronunciation of the fore word. and we don't need to use "를/을" twice. only one is enough...^^ wish to be helpful to u.. have a nice day....^^