Seward added that she wouldn't be surprised if they name their child Diana if it's a girl, as a tribute to Harry's mother.
Betting firm Ladbrokes has Alfie and Alexandra as winners, each with 4-1 odds.
Meghan raised eyebrows with her extravagant $500,000 New York baby shower when she was pregnant with Archie. Photos of the luxurious affair held in the penthouse of the Mark Hotel had senior courtiers "spitting out their morning tea".
And Seward said no doubt Meghan's LA lifestyle will figure in her second baby shower, suggesting new neighbour Oprah Winfrey may be lining up to plan the event.
"I think Meg's girlfriends will be fighting for the privilege of giving her a baby shower this time around," she said.
"Perhaps Oprah might step up to the role as she is a neighbour now? Saying that, though it's tradition that friends throw the shower, her nearest and dearest may host it at Meghan's house - it will no doubt still be very elaborate compared to how we Brits do it. If her last shower is anything to go off, expect harpists and a boujee banquet."
Harry and Meghan sat down to record their tell-all interview with chat show host Winfrey last week.
It came after the Queen stripped them of their royal titles, suggesting a "life of public service" was incompatible with their money-making new careers in the US.
The interview with Oprah is set to be broadcast on March 7. A source close to the couple told the Sunday Times Meghan believes the prime television slot will give her the "loudest way she'll get her voice back".