A new tower or two, an oceanfront pool and a wedding chapel by a famed Japanese architect are among several additions in the works for the JW Marriott Ihilani hotel at Ko Olina Resort & Marina as part of a plan to re-brand the property as a Four Seasons hotel.

Local developer Jeff Stone, who is buying the hotel with plans to close it for renovations next year, also intends to resell revamped units in the existing Ihilani tower to individual investors.

The plans represent a major overhaul and expansion of the first hotel built at Ko Olina 20 years ago, and are emerging two months after Stone announced a deal to buy the property from New York-based investment firm Cornerstone Real Estate Advisers after Marriott’s management agreement expires at the end of this year.

Stone, Ko Olina’s master developer, declined to comment on the development and sale plans for the Ihilani.

However, the envisioned changes were disclosed in a condominium registration report that a Stone entity, Olani Partners LLC, recently filed with the Hawaii Real Estate Commission.

The report said the 387-room hotel is to be converted to 206 residential resort units for sale by Ko Olina Realty LLC, a brokerage firm affiliated with Stone.

The report also discloses to prospective buyers that more residential resort units are planned for construction mauka of the existing tower on part of the Ihilani’s

14.5-acre site, and could be merged with the existing tower and hotel service operations.

According to a design drawing in the report, a new tower with two wings, or perhaps two towers, would occupy what is largely open space next to the Ihilani’s parking garage, an area that includes a grassy field that has been used for NFLPro Bowl activities and other events.

Part of the existing hotel and its banquet pavilion would be demolished to make way for the new tower or towers, which would be connected to the existing hotel building by a new lobby.

Other additions illustrated in the report include a new specialty restaurant, a new arrival plaza and what is described as a "Toyo Ito chapel" overlooking the entrance to the lagoon fronting the Ihilani. Ito is the principal of Tokyo-based Toyo Ito & Associates Architects.

A new oceanfront pool with exclusive cabanas is also on the plan, which indicates that the Ihilani’s existing pool facing the lagoon would become a family pool.

Though Stone and Four Seasons have not confirmed or commented on the luxury hotel management company’s expected operation of the project, the design drawing lists a "new exclusive Four Seasons entrance" to the property that includes a new gatehouse and water fountain along the Ihilani’s entry road.

Joseph Toy, a local hotel industry consultant and principal of Hospitality Advisors LLC, said that generally the development of a new luxury resort tower in Hawaii has to involve selling condo or time-share units to investors.

"The funding from residential (or time-share) sales really drives the economics for construction,"he said.

The last pure luxury hotel built in Hawaii was the Four Seasons Hualalai on Hawaii island, which opened in 1996, according to Toy. He added that the economics for developing a luxury hotel without time-share or condo sales in Hawaii is improving but generally still doesn’t pencil out for developers and financing partners.

That has led to projects such as Aulani, the Disney hotel at Ko Olina, which opened with a major time-share component in 2011, and the Ritz-Carlton Residences Waikiki Beach, a pair of residential condo towers with hotel rental and service operations, currently under development.

Sales prices for units at the Ritz Waikiki project range from $568,800 to

$20 million, according to the project’s website.

Four Seasons doesn’t have any residential resort projects in Hawaii, but operates several such projects on the mainland and in other countries built by real estate developers in recent years.

One such project was a tower completed in 2010 in Austin, Texas, called the Four Seasons Private Residences Austin where units were priced from about $400,000 to $4 million.

In Seattle a Four Seasons Private Residences project with 36 condos on top of a Four Seasons hotel was developed in 2008. Unit prices there ranged from about $2 million to $15 million.

Canadian-based Four Seasons promoted that project this way: "Ferry boats glide along Elliott Bay against a perfect Northwest sunset as a Four Seasons chef serves dinner for eight on your 200-square-foot private terrace with sweeping water and mountain views. Your new home at Four Seasons Private Residences Seattle affords you the effortless lifestyle you always wanted but never found — until now."

At Ko Olina, unit prices in the converted hotel tower were not disclosed in the public report.

Most of the condo units created in the Ihilani will be studios ranging in size from 428 to 929 square feet of interior space excluding lanai, according to the report. There would also be 12 one-bedroom suites with one or more bathrooms, and a presidential suite that includes a library, living room and a full kitchen totaling 2,948 square feet of living space.

Property management firm Hawaiiana Management Co. estimated monthly maintenance fees for studios ranging from $714 to $1,428. The estimated monthly fee for the presidential suite is $4,304.

Specifics about the new tower or towers were not part of the report. New construction could rise up to 150 feet under the zoning height limit for the property, in line with the existing 15-story Ihilani tower.