The only problem I see is Ichigo's thoughts of being vulnerable in his human body. An earlier snippet stated he had the iron skin plus once they got to Hueco Mundo, it shouldn't matter since Nel (presumably) left her gigai and became a purely spiritual entity. Ichigo still has his spiritual pressure, even if he doesn't have access to Zangetsu at that moment.
Ichigo has spiritual presence, yes - but his powers don't work all that great in his body simply because they were always tuned up for his shinigami spiritual form, so to speak, and now they are even worse off with the aftermatch of his royal decree stunt.
Not to say he can't use them, it is just he never really bothered to develop the skill needed. He had Kon and the badge, so there was no real point. All what he did use was more of a bleed off from his shinigami power set, mostly because he's just so ridiculously powerful and not fully in control of it all, especialy now.
He mentions using vestiges of shunpo in earlier snippets, but they were nothing compared to his normal speed as a shinigami. He went from first, clumsy stages to actual shunpo, if still a fairly slow one, within a few minutes during Nel's little 'training', and that's just from being forced to do so.
That he even has hierro and can do some things without knowing what he's doing stems from the fact he's an immensly powerful being who just vaporised his own control switch/OS for one side of his power completely and then merged them.
His reiatsu and reiryoku can do things like use hierro or fire cero, but without the mask to act act as an on/off switch or some kind of OS, Ichigo himself has no idea how. The power responds eagerly, but Ichigo himself enither notices or knows what to do with it and tries to approach it like he does his shinigami power, which is a blind alley, as Nel had shown.
Also, he did manage to try using garganta once, as he menitons earlier. It is just the result was such a hilarious screw up he decided to actually learn it instead of going by trial and error. There is a reason Ichigo's refusing to tell anyone what went down the first time he tried, even if it wasn't quite an earth shattering catastrophe. The fallout of that will come to haunt him eventually, so to speak.