Wow, that's so amazingly awesome!!! Your Melanie cosplay is AMAZING and I'm so glad to hear cast members were receptive to you cosplaying her. Haunted Mansion at WDW has it's own fun details, but it is absolutely not on the same level. I love that your Facebook group has a ton of other people in it to discuss Phantom Manor in, that is so cool!!
Your cosplays of 'random, unaffiliated-with-Disney' characters are so amazing as well. I'm sure kids are delighted to see you, and it's wonderful that you can spread some of the magic and joy Disney has given you to others, through the Facebook group and through your own company!
I'm not a huge fan of scary rides, even still. Despite that, the past couple times I've been able to go to WDW, I rode Cosmic Rewind and the new Tron ride. Both are amazing. If you've grown more willing to go on rides, you will love those ones too. They're both pretty recent, but I think in terms of additions made in the past 10 years or so, those two shine brightly as some of the most fun new attractions.
Visiting Disneyland in California would be awesome, especially since you love Disney so much and truly appreciate the walking gallery aspect so much! And of course, at that point, it would almost feel wrong to not visit all the rest of the parks, right?