Hi Thosha,
i have a suggestion for different spending in chapter 4:
During the Erosian Prelude, if you use the magical charges against the Fucklord in Aram (instead of Ziranthia), you can skip the 200k ProN Embassy (pushed back to chapter 5 1st phase). Aram Country score will be 15 (instead of 14 from using the charges elsewhere). All other decisions remain the same.
That way, during the Counil of Gawnfall, you still get Esmera Score +3 from Aram 15+. You only get the 2nd best Kerannii Score +3 from Aram 15-12 (instead of 16+). However, unlike Esmeras 14- effect, that slightly worse score for Keranii won't change the outcome of the council.
I don't have a great investment strategy for that extra money, in my playthough i just switched out New Givini smithing for Givini Tea House Chain (better RoI than smithing and also unlocks the +15k ProN from the improved restaurant before the next returns).
This left me enough money in investment phase after after the Erosian War (last ch4) to buy the Orc Democracy instead of Water Cleanup, with 47500 ProN left (25k ProN of those are spent in Stineford for the Succubus Bar).