Sorry to hear of your loss. It happens when you are dealing with live animals.
I've read through your thread and from the pics, they are really too small to make a real accurate prediction of gender. If you can get a larger, closer full profile pic, I can try to see if there are any outstanding traits for sexing. ( No guarantees tho on smaller fish. It's just an educated guess based on experience
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This is what I suggest:
The best way to get pairs of Angelfish are to buy and raise about 6-10 fish of the same age and have them pair off naturally OR buy large fish where the genders are fairly visible. So in your case, if you get another one the size/age of your current fish, 1 of 3 things can happen: 1- it will be the opposite gender and you will have a pair. 2- If they both are females, they MAY pair off but you will get no live fry from this but you will know they are 2 females. 3- if they are both males, since there are no females present to fight over, they should get along okay. This would be a winning scenario in my book either way.
So you will want to add the similar sized fish together. If you mix different sizes, the chances are greater that the larger ones will dominate the smaller ones. You also don't want to add a single Angelfish in the tank of an established Angel so if you do add only 1, move some decor around so that the tank looks different and all the fish have to establish new homes for themselves.
As for breeding info, the thread "Wigglers at last!!!!!" is an ongoing thread in the breeding forum by professional and hobbyist Angelfish breeders. Pretty much everything you need to know about breeding and raising them has been discussed on that thread. It might help you to read through it ( it's a long one) so you know what you are getting yourself in to.
Hope this helps