An odd question for a message board like this one. You should probably be consulting someone who really knows what they're talking about before opening a business. There are companies that advise specifically on workplace regulations and ensuring local, state, and federal compliance.
That said, a three minute google search revealed this:
Ask the expert: Sinks in exam rooms | OSHA Healthcare Advisor
So by that, the federal OSHA requirements would appear to be met with just hand sanitizers, but you would need a handwashing station very close by.
However, I also found that several states have additional requirements regarding the composition of clean workrooms in outpatient facilities, including how many you need to have for a given number of exam rooms.
Again, this should all serve as an indication that navigating the internecine rules and regulations governing workplace safety in a medical setting is best left to the experts. Better to find out about these things early before you get too far into the process.
Deciding on whether or not to accept Medicaid is not something anyone should be answering on this forum unless they have detailed knowledge of your expected patient composition and demographics, case volume, new/return mix, referral base, and your business model and operational costs. And it should not be unclear to you what would be done from a billing standpoint for patients carrying co-insurance from Medicare and Medicaid if you do not participate in Medicaid; there are billing compliance regulations for these very situations. Again, another group of experts you should turn to.
Sigh, but once again, a two minute google search returned this:
Medicare-Medicaid General Information - Centers for Medicare & Medicaid Services
Please refer to question 2 and answer 2:
"For services that are covered under Medicare, you cannot bill a Qualified Medicare Beneficiary (QMB), even if your office does not accept Medicaid. A QMB is someone whose income does not exceed 100% of the Federal Poverty Limit and who is eligible for Medicaid paying Medicare premiums, deductibles, and coinsurance for both Part A and B. Even if the person signs a document accepting liability for any treatment costs, you still cannot bill them, as QMBs cannot waive this right under Medicare. Providers who bill a QMB for costs above the Medicare and Medicaid payments (even when Medicaid pays nothing) are subject to sanctions."