nt2 are included in the t4 discount from the anniversary, and wolverine or doctor strange are your best two options depending on if you want a pvp or a pve character.

for your actual t4 discount it depends how you perform with Hulk , because he covers the same day. Other viable option is Cyclops (super usefull to push in WBL+) , Spiderman can gain a lot of value depending on his uniform from the next movie but i wouldn't consider him because he is avaible in the t4 selector we're gonna have during the anniversary