Follow the company's instruction for the mixing of the hard block.
An engine stand that will allow you to position the deck flat so you can do one side, and then the other will go a long way. Pour it in via funnel and use a dead blow hammer on the side of the block to help work out air bubbles while friend pours it in. Use long wooden or metal dowels to help settle it all.
As for plugs, I have not heard of a BBM spitting out freeze plugs, but I have heard of it in BBF. The block literally twists enough that plugs split out. The way the BBF guys handle it by having the freeze plugs tapped to certain size and then they use screw in freeze plugs.