What do you mean exactly? Singlesig just means sending funds to someone else no?
In this context the 2of2 multisig is used between the founder and investor not between the other investors.
Yes and no. Look at how it works for XMR. kuno.anne.media
ah I see, kuno is more like geyser.fund I think we incorrectly called angor a crowdfunding platform,we now call it a p2p funding protocol.