Has your client considered using a Holdco + Operating Co later?
Why LLP now and Corporation later?
Names are regulated by provincial and federal and sometime municipal legislation. You can familiarize yourself with LLP, Corporate Registrations, NUANS, Business Name legislation, the relevant Provincial LLP and Corporate Registration legislation.
Names can also be trade marked.
Professions and some industries also regulate naming.
1 - Canadian Bar Association
Canada has two types of Partnerships - General and Limited Liability.
Reference - What to Look For in a Partnership Agreement
2 - CPA Ontario
The firm name must be registered in accordance with the Business Names Act (Ontario) .
3 - Government of Canada - Business Name
4 - Can two businesses have the same name in Canada
5 - Name Search - NUANS
Corporate name search - Before approving a new corporate name, most provincial and territorial governments require a Nuans report. Proposed names must always meet the requirements applicable to the jurisdiction in which a business is incorporating. Verify with the authority where you are applying to understand their naming requirements before ordering your report.
For Canada (at the federal level), consult the Corporations Canada`s naming a corporation Overview and Requirements.
For all provinces and territories, contact the relevant authority. Their contact information can be found through innovation.canada.ca.
6 - Trademarks in Canada
Canadian Intellectual Property Office.