Here is information from MB Health, which answers most of the questions:
https://www.gov.mb.ca/health/publichealth/factsheets/ppv23.pdf
The question about whether a booster is needed is answered by the Canadian Immunization Guide:
A second dose of Pneu-P-23 vaccine is recommended for individuals of any age in whom antibody response is decreased due to: functional or anatomic hyposplenia or asplenia, including sickle cell disease; chronic liver disease, including hepatic cirrhosis; chronic kidney failure or nephrotic syndrome; and immunosuppression related to disease or therapy (i.e. individuals at highest risk of IPD). If a booster dose of Pneu-P-23 vaccine is recommended, it should be administered at least 5 years after any previous dose of Pneu-P-23 vaccine.
HSCT recipients over 2 years of age should receive a booster dose of Pneu-P-23 vaccine 1 year after the initial dose of Pneu-P-23 vaccine. Refer to Immunocompromised persons for recommendations for HSCT recipients.