1) Well, 7A is a very good seat and direct aisle access so I'd keep that.

2) 6B is a good seat as in no one climbing over him. There will be a little foot traffic but not compared to the larger cabin further back.

So I'd keep 6B and 7A as a good choice for what's available meantime.

13E is also a direct aisle seat and is slightly wider IIRC. Not the seat itself but there is a little more width at the side of the seat. There's the disadvantage of having a passenger either side of you but the screens can go up after the safety briefing/take off.

As for an aircraft swap to Club Suites etc just keep a regular eye on your booking but generally I think the 789 will stick.

There's numerous videos and pictures but here's the mini cabin at 6:00 which might help?





You can see 13E here at 3:40 and the seat is like this (not 13E but it shows the middle seat width)