Cisco SG300 - Allowing one port to access traffic from 2x VLANs

I have 3x SG300 series switches set up in the following way (by a colleague who has since departed) to segregate network traffic:

VLAN 1 - standard network
VLAN 2 - presentation network
VLAN 3 - medical devices network
VLAN 4 - DANTE audio network

All interfaces are set to 'Trunk' with each port set to 'Untagged" on the VLAN it belongs too (all others are set to "Excluded"). This has allowed me to maintain segregation between devices on different VLANs.

I have a LAG set up between the switches with the following settings:

LAG 1, Mode = Trunk, Administrative/Operational VLANs = 1T, 3T, 4095P

Everything has been working well and I have a few question which YouTube/Google haven't been able to answer for me yet:

1) VLAN 2 traffic is spanning all the switches (which is good) however it's not listed on the LAG group - how can its traffic be coming across then?

2) I need to set a few interfaces to be able to see both VLAN 1 and VLAN 4. I tried to set those up like the LAG group but without any luck. What is the best way for one interface to be able to see traffic from two (or more) VLANs?

I am using the GUI web interface to manage the 3x SG300 switches.