It means both actually, but it needs more sentences for proper translation. 여기 제나는 내가 [사랑하는 여자]야 = This is Janna [who my beloved]. 사랑하는 여자 = 사랑을 하고 있는 여자 = 사랑에 빠진 여자 = means the women who in love.

yes you're right. it's nothing far different. in this case "면" has a meaning like "IF" as you mentioned. so 저녁늦게면 아무때나 "could" be considered like, "IF we can meet in the evening, i'm okay on anytime, but if we have to meet in the morning or afternoon, I need to consider" and 저녁늦게 아무때나 "could" be considered like, "I'm free in the evening, other time may not be possible"