Rear discharge Toilet help

I have a cleanout 11" off the basement floor in a finished basement wall. This main is coming straight down from a bathroom directly above on the first floor.
Id like to place a rear discharge toilet up against that main line in the basement ( where the cleanout is located ) and run a rear discharge toilet into that main.

Does this seem like an acceptable option for me? Any concerns?
Your help is greatly appreciated.

Whenever the upstairs toilet is flushed, it's going to burp air into the downstairs bowl, and you will lose water in the bowl. Flush the upper one a few times, and you won't have any water in the lower toilet bowl.

If you intend to add a toilet below the upstairs plumbing, it will need to be vented "before" it enters the waste stack.