You could try network bonding using something like Speedify (the app) to combine the networks. This might end up being a bit more budget friendly than renting equipment.
Otherwise, I definitely reccomend making sure a local recording is saved. Not all apps do this (depends on what you're using). But I work on Lovecast and our app will automatically save this and will let you upload it once you have a solid connection in the worst case scenario.
With that being said, mobile networks these days tend to be quite strong. It's probably worth going to the church ahead of time and doing a test. Best wishes!
If you want something, I bought maidenform full slip from Amazon. It was $50 and fits perfectly. My dress also has a lower than average bra back and this one works well for it.
Have you looked at Bandolino? They have silver flats on Amazon in a size 10:
Bandolino Footwear Womens Edition Loafer Flat https://www.amazon.ca/dp/B07LG92RGB/ref=cm_sw_r_cp_api_i_XtR3Eb5QC2SPQ
I have gold ones in a similar style and completely wore them out, I liked them so much. I bought mine at The Bay so you could check their website too.
Not flower arrangements but an acquaintance of mine had a wedding recently where the bridesmaids were carrying these woven fans and the photos were stunning. Of course I don’t know where this acquaintance got the fans from but they looked like this https://www.amazon.ca/Houchu-Rattan-Handheld-Chinese-Decoration/dp/B096MCVJFF/ref=asc_df_B096MCVJFF/?tag=googlemobshop-20&linkCode=df0&hvadid=549147064504&hvpos=&hvnetw=g&hvrand=1340474163587712960&hvpone=&hvptwo=&h...
There’s an Amazon dupe for MUCH cheaper with ~$20 duties if you’re looking for the look without the price tag HERE. Cant speak to quality myself seems well reviewed