When will we get MHXA banner and how times Raikou banners show up in the future?

normally for limited servants you can see when they will be available in the wiki page, just above the trivia.
Raikou will be back on onigashima re-run and MHXA will get to NA in the valentines 2017 event

https://grandorder.wiki/Minamoto-no-Raikou (not to be mistaken with FGO wikia) This website is the only website to show servants and all the banners that they appear in that I know of. Just look at the top and there'll be a tab for campaigns. Click on that, and it'll show you all the banners. Click on the banner to then see how exactly the banner works, such as whether or not it's one of those rotating banners that feature different servants during certain days. https://www.reddit.com/r/grandorder/comments/7nrzy5/jp_banners_since_launch_v2/ I use the pictures here to figure out whether or not it'll be better to wait and roll the second or third time they come around instead of rolling the first time they come out. We have this advantage over JP so it's make use of it.