Nobody really likes substitutes however until some of the planesets are filled out...
I personally don't have a problem if it adds a historical situation that cannot otherwise be recreated and if the sub is a close match. There is no heavy Japanese fighter to add to this scenario. However the BF-110C is a very close match.
Specifications Ki-45
Data from Japanese Aircraft of the Pacific War [2]
General characteristics
Crew: Two 
Length: 11.00 m (36 ft 1 in) 
Wingspan: 15.02 m (49 ft 4 in) 
Height: 3.70 m (12 ft 2 in) 
Wing area: 32.0 m² (344 ft²) 
Empty weight: 4,000 kg (8,820 lb) 
Loaded weight: 5,500 kg (12,125 lb) 
Powerplant: 2× Mitsubishi Ha-102 14-cylinder radial engines, 783 kW (1,050 hp) each 
Performance
Maximum speed: 540 km/h (292 kn, 336 mph) 
Range: 2,000 km (1,081 nmi, 1,243 mi) 
Service ceiling: 10,000 m (32,800 ft) 
Rate of climb: 11.7 m/s (2,300 ft/min) 
Wing loading: 171.9 kg/m² (35 lb/ft²) 
Power/mass: 0.26 kW/kg (0.16 hp/lb) 
Armament
Ko: 1 × 20 mm, 2 × 12.7 mm (.50 in), 2 × 7.92 mm (.312 in) 
Otsu: 1 × 37 mm (1.46 in), 2 × 12.7 mm (.50 in), 1 × 7.92 mm (.312 in) 
Hei: 1 × 37 mm (1.46 in), 1 × 20 mm, 1 × 7.92 mm (.312 in) 
Tei: 1 × 37 mm (1.46 in), 2 × 20 mm 
Bo: 1 × 40 mm (1.57 in) 
Comparable aircraft
Fw 187 
Westland Whirlwind 
Messerschmitt Bf 110
Specifications Messerschmitt Bf 110 C-4
Data from[citation needed]
General characteristics
Crew: 2 (3 for night fighter variants) 
Length: 12.3 m (40 ft 6 in) 
Wingspan: 16.3 m (53 ft 4 in) 
Height: 3.3 m (10 ft 9 in) 
Wing area: 38.8 m² (414 ft²) 
Empty weight: 4,500 kg (9,921 lb) 
Loaded weight: 6,700 kg (14,771 lb) 
Powerplant: 2× Daimler-Benz DB 601B-1 liquid-cooled inverted V-12, 809 kW (1,100 PS (1,085 hp)) each 
Performance
Maximum speed: 560 km/h (348 mph) 
Range: 2,410 km (1,500 mi) 
Ferry range: 2,800 km (1,750 mi) 
Service ceiling: 10,500 m (35,000 ft) 
Wing loading: 173 kg/m² (35.7 lb/ft²) 
Power/mass: 0.3644 kW/kg (0.155 hp/lb) 
Armament
Guns:
2 × 20 mm MG FF/M cannons (180 rpg - 3 drums with 60 rpg, cannon were reloaded by rear gunner or radio operator during flight) 
4 × 7.92 mm (.312 in) MG 17 machine guns (1,000 rpg) 
1 × 7.92 mm (.312 in) MG 15 machine guns for defense 
Comparable aircraft
Bristol Beaufighter 
de Havilland Mosquito 
Focke-Wulf Fw 187 Falke 
Fokker G.I 
Kawasaki Ki-45 
Nakajima J1N 
P-38 Lightning 
Petlyakov Pe-2 
PZL.38 Wilk 
Westland Whirlwind