When the head gasket failed you likely got coolant in the oil. Coolant and the materials the bearings are made of do not get along. The rattle you are hearing is very likely a rod bearing or two that are failing fast. At the moment you can easily save the engine because it is still turning. If you keep using it you could spin a bearing or a rod bearing can fail, snap the rod and destroy the engine.
A complete engine refresh of bearings rings and seals would be the minimum repair.
Better would be to machine the block and crank to eliminate any wear, new pitons, rings and bearings to match the new sizes. However, with the cost of the parts and machine work a replacement long or short block may be cheaper overall.
The vibration is likely from the bad bearings.
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Sunday, October 8th, 2017 AT 2:04 PM