Is your sister okay with this plan? Is the house in her name alone? A transfer of a one-half interest to your brother would cause a re-appraisal of the one-half interest. Depending on the date of purchase and the value at the time of purchase viv a vis present fair market value, the tax bite could be from huge to non-existent. If the transfer is to create a joint tenancy, a new deed from your sister to your sister and brother as joint tenants will need to be prepared and filed together with...
You should obtain estimates of the cost to complete the work correctly. If he sues in Small Claims Court, you should file a counter claim for the amount of the estimates. You might want to send him a lettter enclosing the estimates and demanding that he pay the amount of the difference between the balance owed on the contract and the cost of properly completing the work.
If he files a lien, he must file suit in Superior Court (not Small Claims Court) to foreclose the lien within 90 days...
You can deed the property to the both of you and create a joint tenancy, which requires the "unities" of time, title, interest and possession. You don't indicate whether you are selling or gifting the interest. There may be an increase in the secured property taxes if you are selling the interest and the value of the one-half interest being transferred is greater than it was at the time you acquired the property.
A corporation can do business using a fictitious business name if the proper filing and publication requirements are met. That will allow the corporation to do business under the fictitious name in the County in which the filing is made. The better question is why do you want to do this? There may be a better way to achieve your purpose.
In order to resign as president you need to send a letter of resignation. You may also be a director and if you want to completely disassociate yourself from the corporation you will also need to resign as a director if you are one. If you are a shareholder, there may be a shareholders agreement that establishes the protocols for the transfer of shares. It sounds as if you should speak to a business attorney in your area to review the corporate documents and advise you in the matter.
I agree with Mr. Pedersen, there is no "standard" commercial lease. That said, typically a commercial triple net lease will require the tenant to make necessary repairs. It sounds as though it should have been obvious to the subtenant that there was a problem. I would approach the original tenant and let the tenant know that their subtenant is causing a problem. Let the tenant handle it since the tenant remains responsible under the lease.