Lens selection for social event

[JoL]

Hello all,
I was asked to take photos at a bigger family event (let's treat it as a wedding for this thread's purpose). Even though the family does not expect much and would be fine with a couple of group shots etc I showed them a few candid shots I had taken at other family gatherings and was able to convince them that they shouldn't miss out on these shots. With that said I am planning on getting candid shots, formal-ish portraits (indoors), group shots, and outdoor couple shots to better over deliver rather than have a disappointed family afterwards.
I am in the process of figuring out what I will put in my photo bag (M43 system), and since I am not a professional I would very much appreciate the input of the experienced people in this forum.

What I have so far:
- Oly Om-d Em-1 (primary camera)
- Second M43 camera (borrowed from friend as backup)
- 2 speedlights
- 2 light stands and shoot through umbrellas for indoor portrait setup
- 25mm 1.8
- 40-150mm 4.0-5.6

What I am thinking of renting for the event:
- 12-40mm 2.8
- 75mm 1.8

Especially in terms of lens selection I am wondering if you see anything essential missing for the kind of photos I want to take?

Thank you for your help,
Johannes