You have a beautiful set up for your fish, great for what you have, but not for breeding.
louisvillelady was able to say things much better than I could.. we will help you in every way we can, but you will have to trust what we are saying when it comes to what will work and what won't.. what is best for all of your fish, etc.
I'm not going to lecture you on which fish to breed. That is strictly a breeder's choice, and personal opinion.
As louisvillelady mentioned, all the fish will be aware as the breeding pair will be letting off pheromones which will drive all the fish nuts. Neon tetras look cute and innocent.. but they are tetras, and tetras are the chihuahuas of the fish world.. cute, tiny, you just want to hold.. but they will nip you for no good reason. They will nip each other, the female betta.. and with her state/mood after breeding.. it can potentially be a death sentence for some fish. The female will need a place to recoup and heal. She is not going to be able to do that in a tank with tiny spastic fish swimming around her.
I too have had fish since I was 12.. my parents had some while I was growing up. 22 years later I still am in love with fish, tropical and cichlids.. have bred different types for a long time when I was younger. I may be new to breeding bettas, but I spent 18+ months studying their care, behavior, history.. learning about the splenden species as much as I could. I spent months researching breeding before I even purchased any items. And I still learn new things all the time when it comes to breeding these fish.
It really is a fun process, and I recommend it to anyone who has the time, space, money it takes to breed. I will answer any questions that I can, if I can't I'll recommend a person or site/group where they can get the answers.
So answer these questions to yourself before you breed them -
Can I, do I want to, spend hours a day doing water changes, cleaning tanks, feeding.
Do I have the space it needs to have the proper set up.. for the breeding tank(s), grow out tank(s), a place to house 100+ jars and a way to heat all those jars. You may not end up with a 100 males, but you may, and you want to prepare. Sometimes you may have to remove females if they are overly aggressive.
Do I have the money to spend on making sure I have everything I need? IAL, tanks, heaters, sponge filters, jars/cups, live foods, etc.. it all costs a pretty penny. If you go with all new things, you are looking at at least a thousand dollars for a simple, small set up. I think in the end, for 2 spawn tanks and 2 30g grow out tanks on my first set up.. with everything needed (including a way to house the jars/cups) I spent easily $1500 - that also includes a few pairs of breed worthy fish. Shipping costs is included in that.
Doesn't mean you will spend that much - you can go a cheaper route by using plastic buckets, etc for spawning and such..
Don't forget the jump in electric/water bills..
A lot of people who start getting into bettas want to breed them, and think it's as simple as just tossing them in together.. sometimes you see people say their fish jumped a divider and bred, or they got success by tossing the pair together and not preparing.. keep in mind after they post that, you don't hear anything from them again concerning the spawn as it tends to end badly. This is something that even with all the right equipment and knowledge, can still easily lose the fry over something we think is very minute - adding new water in after a change that is just a tiny bit off of the water in the tank (chemistry/temp wise). A lot of breeders easily lose 2/3rds of their first spawn or two due to needing to work out the kinks and that is with proper set up.
So you can see our concern - it's not just about whether you breed them or not, and not just about the lives of the fry (we understand nature and how it's natural for deaths to occur, a way of making sure there isn't an over population, etc). It's also about the welfare of the fish you already have and have fallen in love with.
It is also about you.. how it will effect you. Can you imagine getting a spawn, seeing them hatch.. then possibly they grow up for a few days.. a week, two weeks.. then something goes wrong and they all die. Trust me, you will get attached to those tiny little babies quickly. You'll talk to them, feed them, care for them.. and then lose them all. You will feel bad, you may blame yourself, etc.
Is that really fair for you? And if the fry dies, the male WILL know, and will "feel" something. Yes, they live off of instinct.. but they KNOW.
The male of my recent spawn.. After a long battleI was finally able to get him away from the nest (him coming to attack my finger), I got him out and he ended up with 28 fry in his mouth. When he got into his container to recoup he ended up making a whole new nest and started caring for the fry he had hidden in his mouth (unsure how he fit that many in there.. but I counted 28 lol). Over the next couple of days I had to go and remove them.. I used a plastic spoon and a styrofoam cup.. every time I went to get a baby it was a race with him, he would rush up to the baby I was going for and grab it before I could get it. I had to be slow and careful as to not hurt the babies. But he knew what I was doing and he was doing his best to protect them from me. After about 5 days I had them all removed and into the fry tank.
That was over 2 weeks ago. He has built and maintained nests every day since then. He had never built a nest prior when he was in his home tank. Never.
Now he has one going all the time. Part of it is he wants to breed again.. but whenever I look at him and his nest, it pulls at my heartstrings because I felt bad removing him so soon.. now that I have confirmed that he is a great daddy, he can stay with his babies on his next spawn.
So.. as louisvillelady said.. fish know. They can't feel sadness like us, or happiness.. they live off of instincts. But a part of them just knows when something isn't right, or if they want something they can't have. I have other stories too.. but this one is most recent and still crushes me how sad he was after being removed. Some males have stressed and passed on after being removed from their nest. If he is forced to eat his babies because he fears the other fish.. he may become stressed from that.
So yes.. reconsider breeding at this moment. If serious then get what is needed and we will be very happy to help you. Like I said.. doesn't matter what you breed, just matters is the health and well being of you and the fish.
And ugh, I'd freak if I saw one of my tanks leaking lol