Interesting airflow setup in that InWin 303 case with front panel completely sealed off and top mounted PSU placement.
At this point, i see 2 solutions to your problem:
1. Replace your ATX MoBo with micro-ATX or mini-ITX MoBo so that you have enough clearance at the bottom where to put those extra 2x 120mm bottom intake fans.
2. Put spacers (2cm high or so) between the fan and case bottom so that the cables can fit between the fan and case's bottom.
While you can bend the HD Audio, USB 2.0 and SATA cables upwards to fit both fans at current setup, you can't bend the fat and rigid USB 3.0 cable enough to get enough clearance to mount standard fans. Though, if you plan to go with the cable bending route then don't use standard fans since they are 25mm thick, instead use slim fans which are 15mm thick and it gives you much needed clearance, e.g you don't have to bend your cables as much and you may be able to fit them in.
For example:
Noctua NF-A12x15 PWM, specs:
https://noctua.at/en/products/fan/nf-a12x15-pwm/specification
Cooler Master XtraFlo 120 Slim, specs: http://www.coolermaster.com/cooling/case-fan/xtraflo-120-slim/
Gelid Slim 12 PL Blue, specs: http://gelidsolutions.com/thermal-solutions/case-fan-slim-12-pl-blue/
Thermaltake Luna 12 Slim LED;
white, specs:
http://www.thermaltake.com/Case_Fan/Case_Fan_/Luna/C_00002616/Luna_12_Slim_LED_White/design.htm
red, specs:
http://www.thermaltake.com/Case_Fan/Case_Fan_/Luna/C_00002615/Luna_12_Slim_LED_Red/design.htm
blue, specs: http://www.thermaltake.com/Case_Fan/Case_Fan_/Luna/C_00002614/Luna_12_Slim_LED_Blue/design.htm