The big question for Hydro is what things can he do at the same time. He can do all of those things fairly inexpensively, if he doesn't mind having them in a multipower with only one available at a time.
More likely, he'd want at least the following:
* Hard Water Armor: Armor 2 Linked to Deflect 2 [Limitation: Requires water] (3 pts)
* Water Movement: a few points of whichever movement he wants (I wasn't clear if he wanted one of those or all of those; the later would be a multipower).
* Water Mastery multipower:
. . . Water Mastery X (x pts)
. . . Special Attack (+1 pt)
. . . Force Field (+1 pt)
. . . Telekinesis (+2 pts)
. . . Illusion (+2 pts)
That is do-able even in a street level campaign, since for 15 points, he could have 2 ranks in the chosen movement power and 4 ranks (or 5 due to limitations of requiring water) in each of the multipower powers. With more points available, he could split a few of the multipower choices out into stand-alone powers so they can be used simultaneously.
The Hood / Mask situation is tougher. The big issue is the possible conflict on power levels that the players are looking for, and there isn't much the rules can do to help that...
You could go with a Street Level campaign and the player of Hydro would just have to keep most of his powers in the multipower.
Anyway, the Hood/Mask could be based around a "utility belt" concept, like the "Master Crime Fighter" archetype in the book. It uses Conjuring with a limitation to represent various gadgets on hand. Powers from the Intense Training category would be appropriate, especially Attack Weak Point. Take the Versatile advantage to let you power stunt a completely new power once per issue. Maybe take Special Attack with the Variable enhancement and the Time limitation to represent making improvised explosions (or maybe just Concentration if you want him to be able to do it in-combat). Presumably he would have a high Mind, so will also be the best at noticing things, investigations, etc. so he can shine in your non-combat scenes even if he is deliberately not as combat oriented.
I haven't played Portal, but the concept is one I've toyed with in other supers games. It's a lot of fun! Obviously Teleport, with the Gateway and Variable enhancments plus some range and area. Put that in a multipower with a Special Attack with the Variable enhancement (the attack could be a splurt of lava from the earth's core, a high-pressure blast of water from the deep ocean, falling rocks teleported in above their head, etc, etc). Another multi-power slot could be Conjuration, allowing her to bring things through the portal; this works really well in conjunction with Hydro, she can bring through lots of water that he can control. It is a Teamwork action just waiting to happen, that could be a lot of fun to have in the group. Let's see, what else... Deflection, preferably not part of the multipower, possibly with an Enhancement so that when it "reflects" after rolling doubles she can decide who the reflected attack targets instead of just going back to the original attacker. Clairvoyance, where she opens a portal through which she can observe distant locations (possibly with a Limitation that they can see her too!). In some ways she's the easiest because only Deflect really has to be outside the multipower, plus maybe 1 or 2 ranks of personal teleport to get around while attacking, etc.
I don't have time to do full work ups right now, but does that help at all?
