Sounds interesting
About the Firefly drone. The drone was commonly used by the time I started. The drone was somewhat good with proper builds. It is a drome base more on damage not a real overheat drone even help a bit.
The drone still good for some mechs builds now with the new resist drainers. It can take you to R1 with those depending on match maker and player with a full proper mech divined, if possible, to reduce marginal losses.
It is a bit more practical to be use now in 2V2 and 1V1than 3V3 generally speaking. Sure, it is base in opinion and test plus mech owners. In my case I will say is more useful in 1V1 and 2v2 but don't have to be. Skills of the player it is the factor.
For Nemo, top players do not use that one that often now. Used to be use all the time but with the Swoop buff, now is less use and less favorable due to weight comparation to make builds but still a decent alternative. Sadly, it does not create shields damage reason Swoop has been used a bit more now plus weight.