As far as I know the antennae fitted to a couple of Fw-190A single seat night fighters wasn't radar perse but a receiver for the British 10cm air intercept transmitters fitted to Lancs, which operated just like a radio compass. They didn't have a radio-wavelength display to have to decipher but just a direction-finder guage mounted in the cockpit.
Also on top of the two large fuselage fuel tanks already in the Fw-190A and no less than three standard radio sets, electrical control systems, the all weather/night operations package included another heavy radio set, an autopilot kit and improved heating/de-icing equipment throughout. The landing light fitted wouldn't have weighed much.
These are of concern because the BMW801C/D have full throttle heights around 4500 metres and bombers cruise at good speed at 5000 metres and higher. At this height the BMW is starting to lose performance, by 6000 metres climbing or accelerating is a leisurely event, there was not even any ram-air to work with except for special modifications (which introduced drag issues and muted performance gains, but did raise throttle heights).
It was an issue with the Me-110 nightfighters for example, which reportedly had a little trouble sometimes with intercept performance against good heavy bombers operating at altitude, due to the additional weight of night-fighter versions. I remember a good book written by an Me-110 night-fighter pilot who fought against the British heavies, it elaborately described how very hard it was to intercept the fast Lancs, it was along, slow and nail-biting stalking process. The introduction of shrage musik was very welcome for these types.
If you were going to consider a full radar installation, the best choice would be the back-back tandem Uhu with twin DB-603 engines, they really starting rocking the kasbah at 6000 metres with fantastic acceleration and intercept performance at these heights and all the torque you'll ever need for as much special equipment as you want in a stable platform. Plus you want twin engines and a good fuel load in a night-interceptor, raises the odds on making it back to base in the dead of night back in the forties.
The Me-262B night fighter I prefer to think of as a design concept rather than a preproduction series. It had the power to carry plenty of weight with terrific intercept performance, but engine reliability here. Perhaps later when German jets managed hundreds of hours and didn't burst into flames everytime someone said boo. A more conventional contemporary night-fighter could cop a bit of combat damage and keep flying at least. Piston engines were still a very necessary presence at this point in history I think.
As for night-navigation German pilots had a well developed radio navigation system in place by 1943 so most Focke Wulf and later Me-109 versions had radio compasses and direction finders fitted in addition to other navigational equipment (calibrated-gyroscopic and magnetic compasses, plus the usual attitude/inertial indicators). The R-11 kit for Fw-190 models added autopilot and some specialised night equipment from low glare finishes to heating equipment and landing lights. You could really operate most Fw-190 and Me-109G from 1944 onwards in any visibility conditions in daylight, though really an R-11 equipped Fw-190 or Ta-152 was best for night operations as a single seater.
I don't think any Allied day fighters were as well equipped in terms of navigational equipment except for navy models, which had pretty much the same stuff so you could have a chance of making back to a carrier at sea. The Smithsonian assessed a captured Ta-152H-1/R-11 as one of the best piston engine aircraft ever built not so much on the basis of its performance, but its performance being postwar contemporary yet with the sheer degree of pilot/navigational equipment fitted as standard, which was more comprehensive than most jets in the fifties. Much pilot equipment standardised in German production by 1945 didn't become commonplace in front line fighters until the sixties.
Therefore I think Allied pilots had a harder time navigating at night without a specialised aircraft type because much of the equipment fitted standard to German planes wasn't present. British night mission reports tend to talk about astro-navigation and getting lost on depleting fuel supplies a fair bit. A whole squadron was lost once. Germans tended to mis-navigate because of signal confusion with the instruments rather, landing in England thinking it's France because the radio navigation equipment got confused by urban signal clutter.