I wouldn't be in favor of merging them. They have similar, but not identical, structures, somewhat different goals, and very different levels of GM support.

MHOs are expected to be a lot more self-sufficient and need to remain actively managed to continue to exist. Active MHOs come up in a rotation for improvements, but everything has to be paid for with (a lot of) silvers which need to be raised by the group.

CHEs can be as active or inactive as the current officership wishes but carry on as a member perk in either case. Active CHEs earn IPs which can be used to improve the House, provide additional member perks, or gussy up future events.

/seo, wheels and skulls department/