Do we say Al Hamichiya again for the grapes or because sofek bracha lehakel, we omit the one for the grapes?
From Star K website;
If a person ate grapes and, instead of reciting “ al ha’eitz” throughout the bracha said “ al hagefen”, he is yotzeh.3 [If he ate grapes and drank wine, but recited only “ al hagefen” without specific intent for the grapes that he ate, he must recite a separate brocha acharona for the grapes.4
(ii) If a person drank wine and, instead of reciting “ al hagefen” throughout the brocha said “ al hamichya” or “ al ha’eitz”, he is still yotzei.5 [If he drank wine and also ate a mezonos item or one of the shivas haminim, but recited only “ al hamichya” or “ al ha’eitz” without having specific intent for the wine, he must recite another brocha acharona for the wine.6
(iii) If a person ate dates and, instead of reciting “ al ha’eitz” throughout the brocha said “ al hamichya”, he is still yotzei.7 [If he ate dates and a mezonos item, but recited only “ al hamichya” without specific intent for the dates, he must recite another brocha acharona for the dates.8
(iv) Other than the three cases noted above, if a person inserted the wrong phrase throughout the brocha, he is not yotzei and must repeat the brocha correctly.
In an appropriate shiur it was explained that al hamichyah applies only to mezonos and al hagefen only to wine and al haetz only to the specific fruits. Thus, if one says one of them, the others can be said separately. If one does remember, then they are included in the maein shalosh at the appropriate location (such as al Hamichyah veal hagefen).