I don't like brass fittings for oil feed lines , the tee is ok , but the threaded "close nipple" should be steel , over the years I have seen many of these crack , actually almost all of the ones where there is any weight at all hanging off (like a tee and oil sender) have broken off at the threads! If you don't drive the car much , it may take some time , but it will eventually fail , just get a steel one .
you could also use hondabond(what the factory uses on fittings) but do not use teflon tape.
OK , I was afraid of this, what you need is a screw extractor , the type which is square and has one "flute" on each corner , with this type of tool , you tap in in with a hammer , then unscrew it , DO NOT attempt to use the type that looks like a swirly screw, as this will only expand the soft brass, forcing the threads to tighten making removal impossible , as far as the adaptors are concerned, as I stated , you can use a brass tee, but the other fitings should be steel , you should only need 2 , a 1/8 npt close nipple and a 1/8npt to -4 an . The sender is inline with where it used to be and the -4 adaptor comes off at a 90.
In a worst case scenario you could pull the oil filter housing and drill and tap it (this would suck)
OK Fitti , you should also be careful when tightening the fitting , since it is tapered , it is possible to split the boss open if overtightened .
I guess if all else fails you could sell it and get the andretti version.