Hey Kim, I have read through your thread and will offer my opinion on a few of your last questions. First, no - the stallions are not too old to be gelded. The main consideration is their health. The little paint stallion seems to be in very good health, and I think gelding him would definitely be the right thing to do. You say he is already very docile and friendly - if you gelded him then he would only become even more docile and friendly! For me, there would be absolutely no drawback to having him fixed and I would do that right away. Your other 'little' stallion has had a few more issues - as you said. I, personally, would also geld him - but I would discuss it with your vet tomorrow. If your vet feels he is healthy enough right now - then I would get that taken care of right away as well. There really is very little risk to gelding a stallion when done by a good vet with a horse in good enough health. So my suggestion would be to definitely plan on gelding both of them, but to figure out the 'when is best' together with your vet when he comes tomorrow. With what your plans are for your little minis, I don't think there is really any other options that I would consider. Regarding fixing your mare - it's not real common, and it is higher risk to spay a mare than it is to geld a stallion (though sometimes it does occur - usually in mares with really bad heat cycles). With the stallions it is a pretty noninvasive, simple procedure. Gelding your stallions will really take the hassle out of caring for your minis - as you will then be able to continue to keep them all together and not have to worry about them injuring each other or breeding your mare. They can simply be your pets at that point. I think you have also been given some good advice regarding care for your mare. As you are, I would start by first confirming whether or not she is pregnant - and then proceed from there. If she is in foal you will have a lot to learn and prepare for, and if she's not you can get the stallions gelded and keep them all happily together. Also, if she is pregnant - I would still geld the stallions right away... Some stallions are good with foals, but others are not and could be aggressive toward a little foal if you end up having one - not worth the risk in my opinion.
With regard to the age question - it obviously varies - but I think around 25 is a pretty average age. Obviously some don't make it that long, while others live into their 30s. Hope my thoughts are helpful, and as shorthorsemom said - keeping asking the questions - this forum is the best place I have ever come across for answering questions and learning to best care for minis!