We are trying to setup a Testnet multi-sig wallet between windows and Mac users. The Mac provides a MPK starting with xpub it wont be excepted by Windows wallets which issue tpub MPK's. Is there a solution to this?

We are looking at setting up a multisig Electrum wallet 2 of 3. When looking it seems you need to have all three people set up at the same time, this is very inconvenient for us. Is there a way to avoid this?

With the current incentives of mining or transaction fee doesn't economies of scale mean eventually the processing will be in the hands of the biggest most centralized (read JP Morgan or maybe ICBC) companies. Wont we lose our so called independence?

Why is AVG antivirus claiming bitcoin is malware and deleting from my pc?

If I am a merchant and I sell 10 identical items via a website and I check an hour later and 8 people have paid for items how do I know which 8 to send my items to?