Welcome to the forum @sammie! Which iX model are you looking to get? I tried to answer as many of these as I can.
The i4 and iX have heat pumps.
evglobe.com
From my understanding the i5 will use a similar platform to the i4 and iX.
www.electrive.com
There is going to be OTA updates for the iX with the latest iDrive system.
The charging network will pretty much be the electrify america network. I don't think BMW has plans to build their own charging stations.
You will be able to pre-condition your iX before you hit the road.
The i4 and iX have heat pumps.

2022 BMW iX - 600 hp and 300 miles range, $83,200
The BMW iX xDrive50 will be the first iX to launch in Q1 of 2022 and will come with a starting price tag of $83,200

From my understanding the i5 will use a similar platform to the i4 and iX.

All-electric BMW i5 should hit markets in 2023 - electrive.com
A new media report in Germany provides some info on the all-electric version of BMW's 5 Series. The BMW i5 is to be presented in 2023 and will also have an M variant. The main rivals are said to be the Mercedes EQE and the Audi A6 e-tron. + +…

There is going to be OTA updates for the iX with the latest iDrive system.
The charging network will pretty much be the electrify america network. I don't think BMW has plans to build their own charging stations.
You will be able to pre-condition your iX before you hit the road.