Combine text with CONCAT or &

I have first name in column A and last name in column B. Create a full name column C that shows LastName, FirstName for each row, and another column D that shows FirstName LastName for email greetings. Ensure formulas fill down so new rows auto-combine.

Before I publish the membership list, make the combined names easy for use in mailings. Put the formal LastName, FirstName in one column and a personalized FirstName LastName in another, strip extra spaces and capitalize names consistently. Also add a column with an email-safe username: first initial plus last name in lowercase, removing non-letter characters.

I merged names and now entries like ' macdonald, O'neil' or 'van der Meer' look wrong in mailshots. I can’t contact every member. Should I apply simple proper-case rules and remove double spaces, or is manual spot-fixing necessary for compound names? What transformation is likely to improve 95% of cases without mangling legitimate capitalizations?

Every month I rebuild combined name fields and then tidy capitalization, prefixes and spacing by hand. I keep losing credibility when mailings have poor names. Recommend a persistent habit and a light-weight sheet-side rule to enforce name formatting at entry and a one-step cleanup I can run before any mailing that covers most edge cases.