only one bank (between yhilin, ivalan and adran bank) before chapter 4 mean meager profit, and that create snowball effect during chapter 4 reducing your return of 1M, at least, in the end of the chapter. asking more ProN in chapter 1 cripple your income dramatically, for what? cache excavation and yhilin works? near useless.
all the supplier are some of the wrost investment you can do, if we are talking about return or hidden stats, you need them for BoY or the 3AW, if your hidden score are high enough they are investment to avoid (with special supplier the only exception to this rule)
100K for the OoS is a waste of money, 50K is enough. the only effect you have at the moment it's only an Auxiliary Diversity +1 in the erosia invasion, a bonus you can gain from other source, and they impacting way less your income.
my actual plan: the erosian war balance is stable, but this is a WIP before we see the actual chapter 4 ending and obviously at any time one update can change the table and force to retink the plan from the start