Question about Expiditions

Firstly, when is this expidition window going to open? 8 weeks since last but unsure on date as newish

Second, increase in stash size, is this a base increase or an overall increase? For example atm cap is 280 slots, with increase will it be 304 or will it just start at 48 instead of 24 for example (can't remember low number)

Third, I've seen people saying "up to 5 skill points" but is it confirmed how you get those skill points and how it's capped? For example if it's 1sp per $200,000 loot value (and in theory would this count banked $)

And lastly with 3 and 4, I understand the exp boosts would only last the 8 weeks but my understanding is the stash and skill points gains would snowball which each prestige, is this accurate?

Thank you for anyone who can give me some insight as Google and other comment sections are pretty foggy on finer details.