There is no definitive ghetto method for verifying the purity of pseudo. Burning a little on foil helps spot obvious impurities. Don't incinerate the pseudo, just get it hot enough to vaporize and smell the vapor. Clean pseudo has a distinctive smell, which you will always remember once you smell it. Clean pseuedo should brush easily off the glass it evaporated or dried in, and will not clump into hard clumps. If you have lumpy pseudo that is not like a fine sand, you don't have clean pseudo.
Recrystallizing the pseudo twice after you think you have it clean will teach you how much of what you thought was pseudo was something else.
How much H2O2 or HCl is "too much?" I have not noticed a difference between reactions done with I2 from tincture and those done with I2 crystals or I2 prill. But the I2 crystals I have from tincture are very well rinsed until the majority of the coloration is gone from the rinse water. Five washes usually gets most of the I2 in the filter, and the I2 in the filter is rinsed again after that another four or five times as I work the last of the I2 out of the jar it crystallized in. If you think you may have H2O2 or HCl in excess from the I2, you simply aren't rinsing it clean enough to start with.
What you wind up with after a failed rection depends on how much reduction was achieved and how many by products got formed along the way. Fail early on from insufficient rp, and the chances are you will get back pseudo. Fail mid way through and you will have a meth/intermediate/pseudo mix. Fail later in the reaction and you will have more intermediates and meth, and less pseudo. Depending on intermediates, you may dissolve most of your product away in acetone rinses. Some low yielding reactions are nothing more than incompletely reduced reactions that would have yielded better had they been allowed to complete. It isn't really possible to give a definitive answer to the question, because what you get depends on why and when during the reaction you failed. The syrupy mass you describe sounds like a case of serious PEG contamination. PEG, if you don't get it out of the psuedo, will turn to syrup in the evap dish, foul your recrystallization attempts, and reduce your yield substantially.