I can't data mine, but I can cross reference this page with the current investment page and Fulminato's calculator. Here are the changes/feedback I suggest:
1) Saying the word 'dubious' in the sentence: "you will be able to make the dubious choice of turning some of your excess ProN into Sx" seems improper. If this wiki page is trying to be unbiased and informative only, I feel the word dubious should be removed.
2) Footnote  in the bridge repair states incorrectly it reduces the price of the yhilin supplier (after the reunion) from 25k to 15k, it should be 20k to 15k
3) The ROI for the Yhilin supplier is wrong. Since you are including the bridge repair price in your roi calculations elsewhere, it should be
R2: 66.67% to 100%
R4(PDF): 66.67% to 100%
R5: 66.67% to 100%
R6: 33.33% to 50%
4) The ROI for the Yhilin supplier is wrong. Since you are including the bridge repair price in your roi calculations elsewhere, it should be
R4(PDF): 40% to 50%
R5: 40% to 50%
R6: 20% to 25%
5) Late bridge repair (after reunion) does not give the +1 eco, +2 yhilin
6) Late yhilin public works 1 (after reunion) does not give +1 yhilin
7) Late cache excavation (after reunion) is +2 yarra +2 qum, not +5 +5
8) Crystal refiner ROI is wrong. Should be R5: 75% to 90%, R6: 18.33% to 22%
9) Crystal refiner does not give any Megail RP
10) Succubus Immigration needs to mention that it gives -5 IKD morale at the start of the 3AW
11) Succubus guild fees should be +1 eco, +1 yhilin acceptance, not +2 +2
12) National succubus trade should give +2 Qum RP, not +5. (Yarra and Nalili are correct at +5)
13) The currently in use investment page shows what the prices will increase to in not purchased right now. Maybe consider including a column showing that information for convenience?
14) Gasm fall trade is +3 Iris, not +2
15) Yhilini succubi trade is +3 Iris, not +2
16) All 3 versions of the Steinford farm restoration should have +2 Ardoheim, not +1
17) The mercenary offices in the Ari-Yhilinia outskirts are not listed at all.
18) The yhilini brothel reform ROI is wrong. Should be 60% or 140%
19) Yhilini succubi trade is +3 Iris, not +2
20) Yhilini succubi trade ROI is wrong. Should be 36.36% or 50%
21) The magic standardization cost needs to be check. You say its 10k, the current wiki page says 50k, Fuliminato's calculator says 100k. I don't know which is correct.
22) Denmiel mushrooms ROI is wrong. Should be 38.10%
23) Denmiel archives ROI is wrong. Should be 8% or 13.33%
24) Thelitar flowhouse ROI is wrong. Should be 32%
25) Thelitar rentals ROI is wrong. Should be 22.35%
26) Givini smithing has two different prices. 200 k in ch 4 or 300 k in ch 5. The ch 5 price is not mentioned.
27) Givini smithing ROI is wrong. Should be 3.33% or 5%
28) Bank of Givini ROI is wrong. Should be 85.71%
29) Opening the 5 mil Givini ruin gives +2 New Givini, +2 Chalice States, +2 Tak'kan, not +2 +1 +1.
30) The Tarran'kan trade upgrade gives +2 eco, not +1.
31) Tradesmasher guild gives +3 eco, not +1.
(Also, is it really necessary to say that the tradesmasher guild increase the profitability of itself? Did you mean to say speaking to him at the bloody spire during the 3AW instead?)
32) Ivalan bank gives +2 eco, +2 religion. Not currently listed.
33) Kyangan smithing ROI is wrong. (The one in ch 5, not the bonus cycle). Should be 7.14%
34) Kyangan agriculture price should be 250 k, not 300 k. ROI should be changed: 100% to 140%
35) The name 'Mitigate Tanurak's Fuckery' should be changed to 'Mitigation of Tanurak's attack on Zirantia' like the current investment page uses.
36) Gathering complex refurbishment is +5 OE, not +2.
37) The war monumnent, givini mage guild, and stineford succubi tower all need notes saying they help in the Erosian War/Great Thenousain War
38) Tarrak'kan housing needs to say it helps during the Erosian crisis
39) Eustrin Guild (the round 6 version) need to say it helps with Eustrin Final
40) Ardford restaurant (both the round 3 and round 6 versions) and the Givini teahouse need to say that they are required for Orri's quest to take place
41) Ardford restaurant (both the round 3 and round 6 versions) needs to say that it helps in the Second Gathering culinary competition if Orri's quest is complete.
42) Zirantia infrastructure and crystal refiner (round 6 version) need to say they help in the Incubus War Aftermath.