On second thought, I think I once read somewhere that "I've" is used that way in the UK sometimes, maybe for possession. But since I am not sure, it might be very rare,I have never actually "heard" it, and I have probably just "read" about it... I have no way to tell whether that "I've" should be considered as a monosyllabic contraction or a bisyllabic one in the examples you are giving.
In the US, monosyllabic "I've" in sentences like "I've to go there" is just not used, in my opinion. As for other dialects... in the UK, Australia, etc... I don't know. I remember reading that unless "have" is used as an auxiliary verb, it is not reduced in British English, but then I realized they were probably just talking about some variety to teach and not in general, probably some kind of RP. I am always amazed at the number of regional differences in the UK. I believe the only way a student would be able to have a good understanding of BrE is just by listening to lots of English from the major dialects, because if you just rely on teaching materials you are only going to learn about ONE dialect, and maybe not even a common one. I once took a quick look at a book about BrE pronunciation (English Pronunciation in Use, I guess... ) and of course they didn't mention glottal stops, as far as I can remember. So, yeah, you get the idea. What a pity... I love glottal stops! LOL