1) An access port will ingress untagged traffic and place it on the default VLAN, or whatever VLAN you set it to. Traffic bound for MAC addresses on that same port is egressed untagged as well. If you want TWO VLANs to be accessible on that port, you can configure it as a trunk and assign both VLANs to the port and the downstream device will need to be able to make use of VLAN tagging. Additionally, you can set the "native" VLAN on the port so that it will also still accept untagged traffic. Most servers and NIC drivers support VLAN tagging, so it's perfectly fine to do this. Some switch manufacturers DO permit you to leave the port configured as an "access" port and also allow tagged traffic. This achieves the same result as configuring it as a trunk. It can be quite confusing because they sometimes change terminology.
2) If the link between the switches is configured as a trunk, and either allows all VLANs or allows those specific VLANs, then all you need to do is configure either access or trunk ports onto that VLAN and things should work properly.