Hey, Glad you liked it.Coming to your questions :

1.)BluetoothAdapter.getDefaultAdapter().isMultipleAdvertisementSupported() :- Unfortunately not all devices support advertisement at all or there's a term multiple advertisement(some predefined adv. are already there with devices). We can't broadcast data from those devices.

2.) If I set inculdeDeviceName(true) in advertising setting then I receive below failure in AdvertiseCallback :

ADVERTISE_FAILED_DATA_TOO_LARGE : There is a limit of 31 bytes for advertiseData. You can check how we consumed it in AarogyaSetu through my Webinar, Slides or this article. You can debug for how many bytes are there for your data and if its less youcan unset some default set flags in advertiseSettings(if not needed). You can play with it. But also If there is more data, go for GATT. Read about it. It can handle a good amount of data as well as connections.

3. ) Yes timestamp, name, rssi, txpower and some more paramaters there which are helping ur in calculating the risk of an individual. This risk calculation is done backend. We just send all these params there.