chuha to chuhiya is hypocoristic. The spelling (or, indeed, the pronunciation) chuiya is rare; but it is used in the movie Water.
May be there are parts of North East
India where the -h- between high (semi-)vowels does disappear, but I am not familiar with it. The intervocalic, especially between high vowels, environment does seem to soften the -h-, but in my experience it is always heard.
I am doubtful that Yansika is from Hansika.
India is a big country, so it is possible that such a dialectical variant can exist somewhere, but I am not familiar with it.