ㄹ =R?????ㄸ = TH?????????바 = Pa????????????Noooooooooo. Sorry, I hate to criticise someone who went through so much effort, but please DO NOT teach kids to transliterate into hangeul. Please, please, please. This is precisely what I've always tried to get KETs not to do. I teach my kids the complete opposte - ㄹ is neither R nor L. ㅅ is neither S nor SH. There is no TH, V or F sound in Korean. Because there aren't. If you want a fun phonics game please try Phonics Monsters by bogglesworld. And please cut the Hangeul out all together.
I really don't think you should get your students correlating the English pronounciations of Roman letters with the pronounciation of hangeul. Why? Yepoyo says yepoyo, which sounds very different to 예뻐요. For the same reason English words can't be written properly in hangeul (잉글리쉬 anyone?) you can't do the reverse either. The kids may like it but you're not helping their English. I hate to say it, because you've clearly put a lot of effort into this.Unfortunately Koreans have a number of basic pronounciation mistakes that they almost all make as a result of thinking of English words in terms of hangeul. For example, there is no hangeul equivalent to the pronounciation of "u" in the word "up." As a result, if Koreans have to write it in hangeul they pick the nearest equivalent, which is "어", making "업." This does not mean that the "u" sound in "up" is the same sound as the Korean "어." Also, when transliterating the other way, the English "o" sound (although I accept it ha various pronounciation values) can be virtually the same as the Korean "어". There is no u as in up sound in Korean, there is no th, no f, no v, no z, no wo (as in won't, or even as in wood), or . In English many more consonants can be pronounced together without a vowel sound in between, again, as in "English," although this can't be replicated in Korean (잉글리쉬). Basically, I don't think it works to teach pronounciation by encouraging young students to think in terms of hangeul. I think with language learning it's always best to get them pronouncing things right from as early as possible.Again, I'm sorry to do this to you, but I do feel strongly about it as the sounds of English and Korean are so different.
Yu, what I actually do sometimes is write up hangul beside characters where there is a 1:1 relationship. So ㅔe, ㅏu, ㅊch, ㄴn, ㅁm. But, the real goal of this is that I draw stars next to the others (yes, that includes i and o which do not have hangul equivalents due to vowel length). As all but one or two end up with a star, I feel that can really push home that the sounds are not the same.