I believe if you start cycling now, you will eventually lose a villager before you gain a new one.
You will not get a new villager unless you:
- Invite one from the campsite
- Invite one from another town
- Gain one from the void of someone you streetpassed with
- Gain one from the void of someone you connected with
However, once you do gain that 10th villager... Well I believe you can "replace" them by cycling but I'm not entirely sure.