Can I find out how many relays the network has and possibly where they are located?
The amount of relays and bridges over time is measured. It's also possible to see the country-specific amount.
Can I learn about roles the relays play in the network? For example, how many exits/guards/middle (or combination) are there?
The amount of assigned flags (e.g.,...
So far it's just something that might be useful for developers to collect. It's probably nothing that an individual user or relay operator would have to care about at this time.
It's also not even clear yet what the answer to your question really is.
As Roger explained in What is the "TLS write overhead" percentage reported in Tor log entries?, ...