API Activity Dashboard does not show any activity

You might want to increase this value to 500 or so

Your pumps section should look like this:

"pumps": {
        "mongo": {
            "name": "mongo",
            "meta": {
                "collection_name": "tyk_analytics",
                "mongo_url": "MONGO_URL"
            }
        },
        "mongo-pump-aggregate": {
            "name": "mongo-pump-aggregate",
            "meta": {
                "mongo_url": "MONGO_URL",
                "use_mixed_collection": true
            }
        }
    },
    "uptime_pump_config": {
        "collection_name": "tyk_uptime_analytics",
        "mongo_url": "MONGO_URL"
    },

Looks like you are missing one of the pumps that generates the aggregate logs which are required in newer versions (they are faster aggregate records to optimise dash speed).

Have you upgraded your installation? If so, you may also need to amend your tyk_analytics.conf to include:

    "enable_aggregate_lookups": true,
    "aggregate_lookup_cutoff": "01/07/2016",