Thosha Good explanations from you and lostone2. Indeed, having Gasm Trade earlier will indeed make a large Pron difference. Particularly if you can get Sanitation Guild and Denmiel Archives later when they are needed. And bigger Order is also appreciated.
For what it's worth, I have a relatively easy way through Hidden Port: Simon, Robin, Altina, Yarra. Yarra must have a buttplug. Change Yarra for Carina for the last group of four snails. Start the attack by going for the group of two moths, then do the group with two octopi. Yarra's main function is to keep the two mages charged up. Also, with each of the fights, there's no rush. Once the moths and octopi are finished, there's lots of time to regenerate Simon, provide power to the mages, and allow Yarra to recover.