Temptation does not define a person. Tempted to steal does not make one a thief. Tempted to kill does not make one a murderer. Tempted to bugger another of the same sex does not make one a homosexual. while temptation is sinful in the eyes of God it is not sinful in the eyes of society. Homosexuality only occurs when it is performed. There is no predisposition to homosexuality that brands one a queer, only the act.
A scout leader who is a professed queer has performed sexual acts on another male. Such persons are not constrained by sexual taboos or moral controls. Unless they turm away from and reject as sinful their sexual immorality they can not be permitted to be in authority over children.
Your attempt to define a person as a chaste homosexual is an aberration and is not consistent with Catholic doctrine.
(2) But if you mean "homosexual" as in "a man who experiences sexual attraction to a man," then of course a homosexual in this sense can be chaste. He resists temptation -- he resists in thought, word, and deed, by the grace of God, and does not sin.
This is why the word "homosexual" is problematic, because this verbal confusion between the two common meanings keeps recurring.
An analogy: temptation to get drunk does not make one a drunkard, but alcohol dependence syndrome (a particularly sensitivity to alcohol toxicity), does make you an alcoholic --- and it's something you can be born with (e.g. Fetal Alcohol Syndrome.) This hyper-vulnerability may be none of your own doing, but you still have a responsibility to abstain from alcohol for your entire life. Thus you can be a teetotal, sober, clean, alcoholic. But you're still an "alcoholic," --- albeit a "dry alcoholic," --- because you still have that inward vulnerability to alcohol.