Copying effects only copy the base thing. You get 1 sneaky Colossus and 2 blockable Colossi.
When copying an object, the copy acquires the copiable values of the original object’s characteristics and, for an object on the stack, choices made when casting or activating it (mode, targets, the value of X, whether it was kicked, how it will affect multiple targets, and so on). The copiable values are the values derived from the text printed on the object (that text being name, mana cost, color indicator, card type, subtype, supertype, rules text, power, toughness, and/or loyalty), as modified by other copy effects, by its face-down status, and by “as . . . enters the battlefield” and “as . . . is turned face up” abilities that set power and toughness (and may also set additional characteristics). Other effects (including type-changing and text-changing effects), status, and counters are not copied.
An effect that says a creature "can't be blocked", such as found in Rogue's Passage, is not an effect that carries over to a copy of that creature (C.R. 706.2). (Note that such an effect doesn't grant any abilities to anything.) Even if Rogue's Passage's second ability said "Target creature gains 'This creature can't be blocked' until end of turn", the ability gained this way wouldn't carry over to a copy of the creature; the effect is not a copy effect, but rather an effect that adds abilities (C.R. 706.2; compare C.R. 613.1a with C.R. 613.1f). In general, only copy effects and certain other exceptions not relevant here are copied, not effects that say a permanent "gains" a certain ability (C.R. 706.2).
Compare Rogue's Passage with Glaring Spotlight. When Glaring Spotlight's last ability resolves, creatures "you control ... can't be blocked this turn", even creatures that come under "your control" later in the turn, because the part of the effect quoted here doesn't change the characteristics or control of any creatures; rather, it changes the rules of the game (C.R. 611.2c, 108.1). Thus, for example, if you activate Glaring Spotlight's last ability during your turn and it resolves, the tokens you create due to myriad will not be able to be blocked this turn while you control them. (On the other hand, only the creatures "you controlled" when the ability resolved, and no other permanents, will gain hexproof this way, because this part of the effect changes those creatures' characteristics by adding an ability [C.R. 611.2c, 109.3].) See also this thread.
Slight aside to your original question, but having Flash is completely irrelevant here. Blade of Selves doesn't attach itself when it enters the battlefield, you have to pay to equip, which can only be activated as a sorcery, and Leyline of Anticipation doesn't interact with that. Merely flashing in the Blade doesn't do anything.