I admire your lifestyle and most importantly that you and your family are living happily in it. That’s the main point of retiring or being able to not work for so long hours or where you don’t like. With your budget, many people would find it very difficult to live especially in Taipei, including myself, but since you all are adjusted to this range I don’t see why you shouldn’t be able to live here.
Speaking for myself, if I didn’t have certain habits in life, I could live with your budget, but the ego and my psychological side don’t let me. I have to admit I do use a lot of travels and other high cost expenses as a way to pamper myself and to comfort something that is most of the time triggered due to stress. So the rat race… stressed need to spend money in activities that relieve stress… need to keep making money to fuel them. All this could be avoided maybe if I decided to abandon certain stressful things in life. Thus my most money spending habits are not required for survival but because I am too used to them, think about spa massages, stays in hotels, weekend gateway in remote location. For example, I could easily live in a place half price than where I live now, but I don’t want to live a bit more further away or live in an older building, at least for now. And so, there it goes.
Since you and your wife are on board with this and used to it, even with the original budget you got (without adding your new enterprise) I don’t see how you couldn’t live in Taiwan without having all your needs met.
I’d only suggest you look into your circle of people here and some of the cultural differences. Per my understanding you lived in Taiwan before, but I have found new cultural traits and dealing with locals that only surfaced after 10-12 years here and now are such a deal breaker I am considering leaving. My best friends have left and it is not so easy to make new good ones. Relationship with locals, to me, are a game of luck really. Very difficult to find ones with similar interest or mindset and when I do they don’t stay in Taiwan for long.
Throughout my many years here what I found is that most foreigners who I’d consider having very stable circle of friends and by stable I mean similar interest, growing together, healthy friendship and develop a deeper bound are foreigners who have other long term foreigners as friends. Locals are very interesting/interested until a certain level. Most want to get to know you as an exotic item. The novelty for both sides wears off after not so long when more meaningful conversation appears and then you see their level and vice versa. I guess it happens in our home countries too but here it feels more exacerbated because there are so many other layers that act as barriers such as culture, language etc.
Of course those are points to consider when moving to any country but in a western country, for example, there are much more similar cultural traits than Asian ones. And even among Asian countries they vary a lot.
So since you got everything nailed, just my two cents in an aspect that is not financial but should be considered when taking a big step such as this. All good luck to you and your wife in this endeavor.