i honestly don't have an answer for any of these because i don't know where the show is going. even with what we know about episode7, i have no idea what will be in episode 8. condal kinda said on sdcc that there will be no big sequence in the final episode and it's also said that because they had to cut this season to 8 episodes, the next battle will be moved to season 3. tho - is it the fall of king's landing or the battle of gullet?
(let me remind you, that the show kind of forgot that gwayne is supposed to be in KL not on a roadtrip with criston)
but in my opinion? i'm doom and gloom when it comes to this show, so no, i don't think they will see each other again (which actually would be fine and canon, but you would think they'd make their last scenes more meaningful? but i digress.) i do think alicent will grieve him tho , for at least one scene that hotd characters are allowed to grieve their loved ones, but yeah, i think she will.