FabFilter

I typically have 2-4 EQs and on a single instrument, not even mentioning all the other filters I typically automate. I also tend to leave all my EQs on Zero Latency rather than linear EQ. Is there a downside to this?

It isn't a problem. Professional mix engineers mix and match EQs all the time. One EQ may be used for cuts before a compressor with another EQ model coming afterward for boosts. One plugin may be used because it has a lowpass that sounds good in a particular situation and then a highpass or other equalization may come from another plugin. Often one EQ is used for it's character and another for making more surgical adjustments.

Electric guitar is a great example of a situation where there is generally many stages of equalization. There is often a tone control right on the guitar. Each stomp box may have tone controls. The amp generally has tone controls and sometimes a graphic EQ as well. Mic placement on the cab is a form of equalization. Then you may have cuts and boosts on that guitar's track in the mix which might be followed by EQ on the 2bus and then the whole mix may get further EQ'ing in the mastering process. Finally, and completely out of your control, the speakers and environment your track is played in will EQ the sound further.

I wouldn't worry about phase smearing at all unless you are hearing something specific you don't like. Ultimately, trust your ears.

Alright thank you very much.