I wouldn't use the expression 'open sth up for discussion' in the way you are trying to in your examples. It's not only ungrammatical, it's also not the best choice of expression for the meaning I think you want to convey.
English cannot tolerate such a long gap between the beginning and the end of the phrasal verb. If you really want a long noun phrase, you need to re-order your sentence, e.g:
This opens up for discussion the topic/question/etc. of [long noun phrase].
But I think it would be more idiomatic to use a different expression, because 'open up for discussion' is not generally used with an impersonal subject ('It' or 'These developments') but usually only with a real human agent ('he opened the issue up for discussion in the meeting'). So I think you would be better off choosing a different expression, e.g:
These developments raise the issue of/prompt a discussion into/lead to the question of ...
or other suitable expressions.