Within the given budget there is no perfect setup, you will need to compromize somewhere. Don't want to talk it down, just thoughts about what compromizes the setup includes. It is your choice if you can live with it for the time being:
- The camera has got a 15mm sensor diagonal which is small compared to APS-C or FF. There are different ways to look at this point:
EITHER the scope might deal with that image size even without the flattener, so if that is your camera for a while you could use the money for the flattener elsewhere.
OR: the field of view is limited by the sensor. The sope could be used for larger objects with a larger sensor that definitly needs the flattener.
- The mount looks tiny. With the small pixels the resolution of the camera you have a theoretical resolution that the mount will probably not reach. If that is your mount you might opt for a camera with larger pixels on a larger sensor without loss of detail but larger field of view that works well thanks to the flattener
- The scope is a doublet. Be prepared for color finges. If you go the mono camera plus filter wheel way you can focus each color individually, reducing the CA. When shooting L they will still be a bit blurred but mono images yield better results in deconvolution. If you go for an OSC camera one color will be blurred, probably red. This can be partially corrected in the software with some effort.
- A color camera cannot be used for narrowband. The closest you can get is a dual band filter which is expensive. A mono plus filters offer far more imaging options but is more complicated to deal with. If you like nebulae Ha is the way to go. If you like globular cluster and galaxies you don't need an Ha filter and an OSC camera is fine.
- If you think about planets: the setup is not suitable for planets at all, you probably know that.
Being future save is often discussed here. This setup won't serve you for years, you will sooner or later start replacing things. You could start with a more future save mount (e.g. SW EQ6-R). To stay within the budget you could get a not too old used DSLR. Canon T3i is not too bad and cheap, most people here recommend Nikons, please ask them for details. You could ge exactly the opposite route and start with a future save camera which is a cooled mono with a filter wheel, e.g. the ZWO 1600 starter kit with mini wheel and L-R-G-B-Ha. I'm really on the fence with doublets. After long research my first refractor was quadruplet (a triplet with the flattener included, TS offers some and WO has got one at least afaik). The scope choise depends on if you want to do visual as well. As you probably know there is no scope that is optimal for both. A scope with the flattener included has got less back focus so that you cannot add a diagonal at all or need a special short one. Looking straight always works. A triplet plus a flattener offers the same quality as the quad but here you have an option for visual plus diagonal as you have with the doublet. CN is full of correct spacing of flattener and sensor, you have to be aware of this. With a quad you don't have to care about this.
Re missing bits: I recommend a decent flat field like Gerd Neumann's Aurora. It is not expensive for small scopes. I know others will now tell you the T-shirt is fine or use your tablet computer, copy pad, etc. I keep on watching the "help processing" threads with vignetting issues. With 3 different scopes and 3 different lenses I don't even know how the v-word is spelled thanks to the flat panel.
The pros of "your" setup is the high qe of the camera, the short focal length that is ideal for a beginner, the low weight of the scope and the correct decsion not to go unguided. I think the ASIAIR is a good choice compared to a computer that consumes lot of power, is sensitive to dew and in case of a certain operating systems that keeps on updating all the time, relatively trouble free. All in all the setup won't cause much trouble compared to popular combinations like SCTs on an AVX or long and heavy newts with coma or focus problems and high sensitivty to wind. I'm really concerned about the color finges of the doublet. Thoughts, anyone?