None of these. The only one that "very" goes with is "high" and "very high selection" is not a normal things to say. "very luxury" - nope "very supreme" - nope "very elite" - well sort of, but nope "very high" - ok, but then you need an idea of what "high" means here, very highly talented, very highly acclaimed, Take the "very" out and it makes more sense. alongside an elite selection of - "elite" means carefully selected, from many others, many available, but few chosen. "very elite" - never used. . Edit Ok, I googled it. People actually use "very elite" and almost a third as many actually use "very supreme". OMG even more use "very luxury" :( Very supreme is just silly. "supreme" means the top. Very the top? Soon we will have "very maximum" Very better, very larger and very largest. :( Despite the web illustrating the best and worse of language, I still think none of the above work in this sentence.

None of them works, really. Perhaps 'a very distinguished selection', meaning that they are very accomplished musicians. They could also be 'highly distinguished'. A 'high selection' doesn't sound natural, but you can use 'highly' as an adverb to emphasise an adjective.

The word "very" gets called driftwood a lot, but I don't see any reason you can't say "very elite", besides not really adding anything relevant. But yeah, only "elite" really fits here. You could say "luxurious selection", although not for musicians really. But "luxury selection" itself sounds more like a product marketing word to me.

I agree with Nanren, Elite fits the best however it would read better as: This years line-up includes an array of talented actors alongside an elite selection of international musicians.

Became so over-blown that I shifted to an answer