M question is the interaction between Barracuda Slam and the Unchained Rogues Finesse Training
With a successful Swim check, you can move half your speed as a move action or your full speed as a full-round action. You can run and charge underwater, though the maximum distance you can move while doing so is half the normal maximum distance. Further, while making a charge attack in water or on land, you can add twice your Strength bonus on the damage roll for your first unarmed strike on your turn.
Specifically the part highlighted in bold. When used with the Rogues Weapon Finesse, does that mean I add twice my Dexterity on the damage roll?
Sadly, no. While Finesse Training does modify the dex bonus for two-handed or off-hand weapons, "any other effects that would increase the multiplier to your Strength bonus on damage rolls (such as the two-handed fighter archetype's overhand chop) do not affect your Dexterity bonus on damage rolls."