To equip the serving tray in Concept Matrix, use the Off Hand weapon id Base 4 - Variant 1 - Model ID 9032
To display the beer mug, use the emote /toast prior to going into GPOSE.  In Gpose, press 1 when the animation shows the beer mug and then load this CMP file.

Actor is 0 Height with 100 Bust size Miqo Female.