Can more than one Roku be used in one home?
Yes. I have one on each of five TVs (four bedrooms, living room).
Your channels are added to your Roku account, so all units linked to the same Roku account get the same stations. Add or delete on one Roku, add or delete on all.
The limitation you can run into with multiple streamers can come from the channels themselves. Some may place limits on how many simultaneous streams you can have at one time.