A: First, I'd want to know more about how the property was acquired in the first place. Are you sure it's community property? If it was given to only you as a gift even after marriage (eg, because your dad paid for 100% of the land but put you on the deed), it's still likely separate property, which your wife would have no claim on in a divorce. (Only community assets are subject to the court's equitable division of marital property - but do keep in mind your separate assets may sway the court on what's truly "equitable").
Are you also asking about what happens to your dad's interest in the property if he dies and leaves it to you? Like gifts, property acquired through inheritance is separate property, which your wife has no claim for in divorce.
If you did in fact contribute community property assets to buy the land with your dad, then yes, your wife has a community property interest in your interest in the land. If you want to convert a portion of your community assets to your sole and separate property, you'll both need to hire lawyers and execute a marital property agreement. I wouldn't attempt to do this without lawyers.
A: In Texas, estates are administered as either independent or dependent administration. A dependent administration requires a much much greater level of court oversight and approval for anything the executor wants to do. Unless the will provides for independent administration, or if the estate beneficiaries consent to independent administration (your issue), the court will require dependent administration.
Whether you should sign or not depends on whether you trust the executor. Agreeing to independent administration will generally lower court and lawyer fees, but at the expense of oversight by the probate court. A Texas attorney can advise you on whether agreeing to independent administration is advisable in your particular situation.
There is no due date, per se, when the executor must make a distribution to the beneficiaries. You should know that creditors (as a general rule) have 4 years after opening probate to come forward with a claim against the estate. A particularly cautious executor may justify holding back distributions to beneficiaries until the statute of limitations period runs. Beneficiaries do have some rights if the executor isn't distributing gifts under the will promptly - they may request an accounting of estate activity 15 months after the estate is opened, and can petition the court to require the executor to distribute.