Are there fewer empty blocks?
No, that's irrelevant.
Have transaction fees increased?
Yes, before the halving, the norm was around 60 Satoshi per byte but now is at 90-100 Satoshi (as of late).
Have any miners dropped out?
Yes, there was some overall hashing drops after the halving which makes sense: less reward and profit ratio = more miners stopping the process.
Is there a consolidation with some miners buying other mining companies?
I think you meant rigs instead of companies. As long as it would be efficient enough to make a profit then yes, but very minimal.
Has the price of mining hardware dropped?
The older ones always drop whenever a much more efficient miner comes out plus whenever they turnout to have lesser profit over time.
Is there any indication of future changes that miners will adopt?
Time will tell...