no MS itachi against akatsuki individually:
1. itachi over deidara: sasuke beat him normal sharingan so itachi definitely could
2. itachi over hidan: full knowledge right? itachi knows about hidan's abilities and look what shikamaru was able to do with that, manhandled him. itachi is just as smart maybe even smarter (in analyzing battles) than shikamaru. itachi sharingan allows him to dodge hidan's SLOW attacks then itachi just beats him rather easily i'd imagine
3. kakuzu over itachi: reason for this is that kakuzu has several hearts, more experience, and just as many jutsu. kakuzu survived a battle with hashirama so that means he is extremely skilled. normal sharingan itachi doesn't have any jutsu as powerful as rasenshuriken so kakuzu wins. until we know more about kakuzu's battle against hashirama (which we wont) then we have to assume kakuzu won or it was a draw. itachi is weaker than hashirama so he is weaker than kakuzu.
4. oro over itachi: sasuke didn't beat oro and neither did itachi it was just a quick duel. full knowledge so oro knows about the genjutsu so wouldn't do anything stupid. oro is extremely hard to kill so he could beat itachi normal sharingan. also itachi was weak stamina, even weaker than kakashi, so a drawn out battle would not be to his advantage. itachi is stronger but oro immortal gives him advantage in long battle so he wins.
4. nagato over itachi: really normal sharingan against rinnegan it isn't even a match nagato wins. even with MS (until it is stated to be stronger than rinnegan it is weaker because sharingan is weaker than rinnegan) itachi loses
5. itachi over sasori: reason is full knowledge. if itachi knows sasori's moves and weaknesses itachi has a clear advantage. only thing that switches tide in favor of sasori is if this is a battle where there isn't full knowledge but since it isn't, uchiha prodigy wins
6. itachi over konan: fire is her weakness and itachi excels at fire style jutsu. itachi has her in smarts, experience, and jutsu so he wins
7. kisame over itachi: reason is samehada. samehada sucks out itachi's chakra which low levels of it is his weakness. normal sharingan has no defense against kisame's powerful jutsu. plus if kisame fuses (which he may have to in order to win) itachi no MS is no match
8. madara and zetsu i'll leave out since nothing is known about them. however, if i have to pick I'll have itachi over zetsu since madara said he's not a frontline fighter. I'll also pick madara over itachi since itachi has no counter against space-time which means madara has the advantage. also, if tobi really is madara, it will be normal sharingan vs normal sharingan and i'd have to assume that madara would have the advantage since he has had it longer and is the most powerful uchiha
summary: itachi no MS loses these battles on the assumption that s-class shinobi such as the akatsuki have a defense against genjutsu. if they dont i believe itachi wins most battles except for kisame and nagato. MS itachi wins most if not all of these battles as well except for maybe kisame because of his overwhelming chakra mass and regenerative abilities and nagato