Great questions -- and you’ve stumbled upon a reason that it really helps to have trademark counsel advising you so that you don’t waste time or money. The short answer is: it depends.
First and foremost, two companies in different states can have the same name. (Exception: you could not file a business under the name of, say, “Coca-Cola, Inc.”, or other household name). Business registration is done at the state level. The only thing your Secretary of State cares about (and is looking for) is whether there’s another company in your state with the same name. It doesn’t research (or care) if other companies in other states do the same. So regardless of who gets the trademark rights, each of you can use the same company name -- provided you stay in different states.
Related: How to Avoid Trademark Infringement
Now, for the trademark. You’re only entitled to federal trademark protection if you can show that you are using the mark in interstate commerce. That means you’re soliciting business outside your state (as well as inside). Screen shots of websites are useful. However, if you’re marketing yourself as a local photographer for kids in Snohomish County for example, that contradicts your “interstate” claim, which means you can't get federal trademark protection. The same goes for the other photographer, so that could be a reason to oppose his/her application. The trademark process gives you an opportunity to oppose a registration. But this is not a tactic to be handled lightly, and you’ll want to speak to a trademark attorney to make sure you have the right grounds to do so.
Also, if two of you have filed for the same mark in the same category, the likelihood is that the examiner on each case will pick up the other application and see a conflict. If there’s a conflict, unless the two of you can work it out, the Trademark Office may refuse to register both applications. When seeking a mark that you can protect, the process becomes a lot easier if you choose a brand that has no exact (or even similar) conflicts. You have several options -- some of which are more expensive than others. At this stage, you’ve revealed enough curlicues that you won’t want to go this alone. The trademark process is far more exacting and persnickety than many people realize.