Texas Import Taxes/Use Tax/Sales Tax

Hello! I am Texas based and I have questions regarding taxes if anyone could help me give an advice.

I host a non-profit "group order" where people would pay me for the items they want to buy, then we would consolidate all these items in the warehouse (from Asia) and have it shipped to my address then I ship these out to these people. We all split the shipping costs evenly based on the weight of the items they claimed and we do this to save shipping fees since it would be expensive to order one item and have to pay $30+ to ship it to the address rather than ship all these items altogether and pay less than $15 for the EMS + DOMS altogether.

My questions are:

  1. Since this is all non-profit, this would not be exactly fall under business right?
  2. I declared the item values for these packages. How much would the maximum declaration value be before the customs start charging me and how do I calculate this so I can charge the people ahead of time? I don't wanna end up having to pay out of my own pocket and charge them later since anytime I could have an emergency and I probably wouldn't have the money.
  3. Some states (like NY) have 4% state tax and 4.65% county tax totaling to 8.65% tax per item purchased. These taxes would have to be "self-reported" to the IRS and I was only made aware of this because a friend recently got audited after 2-3 years later of hosting group orders and she had to pay $700+ for $15,000 of group orders. How does this differ to the state of Texas?
  4. How do I file these taxes and who do I contact to get more information on this?

Any advice is highly appreciated. Please ask me as many questions as you can to clarify this whole situation. Thank you!