You cannot blindly say "run prevention matters, ergo Heyward/Almora is the play" because the question isn't who is the best hitter (or fielder) but who provides the most value when you weigh the positives and negatives of their bats. I think you should try and "hide" Soler in right field against the Dodgers for a few reasons
1. Here is Jake Arrieta's spray chart in 2016 versus LH (assuming the Dodgers go with a similar lineup they had in game 2 where they started 7 guys who hit left handed)
http://www.fangraphs.com/spraychart...6&cht1=hangtime&cht2=battedball&vs1=ALL&vs2=L
That's a lot of going the other way but not a ton of guys getting around and pulling the ball on Jake.
2. Jake's 27.9% fly ball rate was 11th lowest in the league
Jake is obviously not pitching as well lately as he did in April/May but his flyball rate is still quite low and not the kind of pitcher who you worry about giving up a ton of hard hit flyballs to right field on lefties
3. Jorge is a power hitter
When you're struggling, the key to getting out of the struggle is not to try and string together more hits but to get harder hits. The Cubs right now are in "trouble" offensively because they are simply not getting XBH. But Jorge is the kind of guy who can go 1-3 with a double or a HR at a higher frequency than Almora or Heyward will do that.
All in all, I do not see the need for a strong defensive right fielder against the Dodgers with Jake on the mound.
If I was making the lineup today, I'd go
Fowler - CF
Zobrist - 3B
Bryant - LF
Rizzo - 1B
Soler - RF
Russell - SS
Baez - 2B
Montero - C
Arrieta - P