The Ohios and their replacements are a platform, not a missile or a warhead. The new SSBNs will carry a Trident derivative, probably a slightly tweaked version of the D5 (as will the postulated replacement for the British SSBNs) and the warheads will be the same designs with the same yield and functionality as currently deployed because there is nothing to be gained in spending 50 billion dollars to develop and produce missiles and warheads that would be only fractionally better than what they replace.
A the moment the Chinese have no usable SSBNs never mind the small number (three minimum, one on patrol, one working up, one being refitted and if possible one spare above that) needed to maintain a credible second-strike worldwide retaliatory capability all the other members of the Big Five possess.
As for the capabilities of missile systems the Chinese see India and Russia as their most likely nuclear foes in any future shooting war; unlike the insular and isolated US such exchanges can and probably would be conducted with IRBMs and nuclear-capable cruise missiles hence their interest in developing such weapons and the lesser regard they have for ICBMs and SSBNs.
None of the other Big Five nations or the adjunct non-NPT nations with proven nuclear weapons (Israel, India and Pakistan) allow outside inspection and verification of their warhead stocks; the START deal is purely between the two 800-lb gorillas in the nuclear destruction biz. Just because China is big doesn't mean it's on the same scale as the US and Russia; I'd worry more about India's nuclear weapons stocks as they face an existential threat from their nuclear rivals, Pakistan.