Reman It depends on if you have a AFHDS-2A compatible transmitter module in the back of your 9X. They were sold with either these or one running the DSS protocol.

Reman They will work with the TGY i10. Just make sure the transmitter is set to use AFHDS-2A and not just AFHDS.

Reman I've fitted Racerstar 1407 motors on mine. Fly's pretty well on 3S.

Reman Going by the specs I'd say the best props would be something like 5040 or 5045. The max current is a bit tricky, But I'd be thinking if the specs are accurate we'd be looking at something around 16 to 20A on 3s, And 25 to 30A on 4S. Maximum thrust is really hard to guess at, But (Again, Going from the specs) with 5045 props on 3s I'd say between 550g and 650g. And on 4S I'd be expecting to see 850g (Give or take 100g). They actually look like reasonably nice low price range motors. Considering the height of the bell, The bearings could have been spaced further apart, And their's no mention of the grade of alloy used to make them, But that's about the only slightly concerned things I can say about them. If the bearings are OK then for a mega low budget build they could be fine.

Reman You can use most 30.5 x 30.5 FC's, Just make sure it's got at least 6 motor outputs. I used an Omnibus F3 on mine and it flys great.

Reman Yeah, Its got both 16 and 20mm square bolt holes.

Reman I read on another site that it was 20g. It seems a little heavy if you're just looking for an outdoor 2" frame, but if you're after a frame and prop guards for indoors, 20g isn't really that excessive.

Reman When you connect this FC to Betaflight it calls it a "MKF7", A bit of digging shows that this probably refers to the MatekF7. In Betaflight the target with the closest name is the "MatekF722", So as this board has a STM32F722 processor I decided to give that one a try. It flashes OK and everything seems to work. Because this choice was based more on assumptions than knowledge I'm not saying this is 100% definitely the correct target, But it seems to work OK, So it probabbly is.