Above post is correct. Surge protector should go upstream of the Victron, always. (wired between victron and shore). Why? power-surge hitting the victron multi directly could damage it.
Are doing a split + sub panel? Or are you leveraging the new AM Solar Smart Phase Selector?
>>> 1. The power from the Victron will most certainly be cleaner that virtually any RV park shore power hookup.
On battery-only, yes. Otherwise the Victron will assume voltage and frequency of the inbound source in pass-through or PowerAssist mode.
>> 2. Should the surge protector take a dump, I would still have 120v power until I get a new surge protector installed. (Because you know it won't fail during a nice sunny day between Monday through Friday.)
I don't follow. If your surge protector is installed in line with your victron (before or after) and it dies then you are dead in the water. This is the primary reason I use a portable unit that installs outside. If it fails, it takes less than 10 seconds to remove from the system.
>> 3. If the shore power did fail would the surge protector keep the inverter from feeding power back to the grid? I am guessing it would.
no, not necessarily. But it doesn't matter. The Victron Multi will not feedback a material amount of power to the grid if programmed / configured correctly. You can configure a Victron/Quattro to do so in ESS mode but that is a complicated setup / programming and not applicable to your installation.
On a side note, from Guy Stewart @ Victron:
"In a situation where grid feedback is strictly forbidden, and even a few watts will cause issues with your utility meter, or power company you should not use ESS which keeps the AC input grid connected at all times. Even with all feed in / feed back options disabled there is still a chance with ESS that there is some non-zero amount of power flowing back to the grid. For example when the inverter is assisting the grid to run a very large load with solar on a full battery and the load stops, it could allow some small amount of power back into the grid."
On another note do you have a pre-programmed Victron Multi or are you going to try and configure/program it yourself using Victron Connect?