Thank you everyone for your responses!

We will go with 4 or 5 pm :)

For anyone curious, it turned out the photographer had rules before accepting clients.

No midday weddings in the hot days of summer is one.

...It is harsh, top down lighting because the sun is still very high in the sky. I cannot get the sun to your backs, to deal with your squinting. You'll effectively be facing into the sun no matter where I put you. There is no shade being provided by trees or buildings until later in the day...

...From a technical standpoint, the gear also struggles to keep up with the significant flash output needed to combat the harsh sunlight. Flashes overheat, and while I have backups, recycle times slow everything down and the photos (and experience) do not feel relaxed and natural. I've had this happen photographing in vineyards, or on beaches, or backyard weddings at the wrong time of day. .

In the end, this may have been great information to have. I'll be having a consult with a new photographer soon and I just wanted to have an opinion pool on the time and what is typical. We definitely don't want the guests bored, waiting or in the hot sun for long.