We change rooms all the time starting with a room reservation, then changing when the public discounts come out, and usually changing again when the passholder rates come out. You will not lose your ADR’s. We never change to a package though, that is really a different reservation that has to have tickets, whatever you have paid so far on the room only reservation will be refunded to you from Disney, it cannot be applied to a package… If FPP is booked with separate tickets, say those you bought from Undercover tourist, they will stay as long as you have an on site reservation, if you cancel in the 30-60 day out timeframe (before 60 days you will not have made any FPP). You need to book the new reservation before cancelling the old to keep the FPP. If less than 30 days they stay as long as their are tickets linked. You would have had to buy tickets separately at this point to be able to book FPP at 60 days out with a room only reservation. You will not want to change to a package though, as you would then have to buy another set of tickets. Tickets bought from another reseller cannot be applied to your package. If you really want a package, book a package now. If you don’t care about that and wish to have the flexibility of room only, stick with room only and separate tickets. I would not change between them anywhere near your 60 day FPP day.
Also, you do not need to book a package with your travel agent friend to get her advice/help. You can book a room only through her. Her commission is less as the price of your room is not as high as the price of booking room/tickets/dining, but she can still book it. Don’t get caught in a trap thinking a package through an agent gets you more from them than a room only.
Hope this is helpful, let me know if you have more questions.