The two of you have three main tasks between now and the official launch of your party. First, you must decide on a name. This will presumably reflect the party's identity as both non-sectarian and pro-union. The BBC headline announcing your decision illustrates the dilemma that you face. It said that you weren't just forming a new party, but a new "unionist party." To any nationalist voter this means automatically that you are not non-sectarian, but sectarian--the mirror image of the SDLP. (If you don't believe me think of a splinter party from the SDLP that described itself as a "non-sectarian nationalist" party.) You can declare yourself to be pro-union all you want as long as you don't have unionist in the name. That means that you should concentrate on your ideological message: something with either liberal or progressive in the name. But the PUP may have spoiled the label progressive as much as the existing unionist parties have spoiled the label unionist. I suggest you take a hint from the English-speaking "white" colonies in Southern Africa. In 1910 when a group of moderate Afrikaner parties came together to form a moderate Afrikaner nationalist party they called it the South Africa Party. This became the ruling party and then as the United Party the official opposition to the National Party, which invented apartheid. In Rhodesia in 1974 when a new moderate party was formed in opposition to the pro-apartheid Rhodesian Front party of Ian Smith, it called itself simply the Rhodesia Party. I suggest you call yourselves simply the Northern Ireland Party. This name will suggest that you are pro-union without all the negative connotations for nationalists of either the words unionist or Ulster. An alternate name is the Liberal Party or the Liberal Party of Northern Ireland. One of the predecessor parties to the Alliance Party was the Ulster Liberal Party, which relied on the corporate vote at Queen's University.
Second, I suggest you come to a de facto strategic agreement with the PUP and TUV to stay out of their areas if they will stay out of your core area. This is in order not to waste votes. Each of these other parties is competitive in only one or two constituencies. The Assembly with six seats in each constituency can support a maximum of six parties in any single constituency. The more realistic figure is five or even four. There are already five well-established parties and you will be competing for that last slot. Ideologically your logical competitors are the UUP, Alliance, and PUP. If you agree to stay out of East Belfast and North Belfast you should be able to neutralize the PUP so that you can concentrate on the UUP and Alliance. You must then decide on which districts to spend your limited resources in contesting. This should be based on your existing presence, the seats that the UUP is weakest in and Alliance has done well in. But you are in a better position to judge this for yourselves than I am.
Your third task is to come up with a party platform stressing your ideological positioning and innovative ideas. You might want to imitate Sinn Fein and steal boldly from Alliance or the PUP as the Shinners have stolen from the SDLP. But your positions should reflect your identity: pro-union and non-sectarian. I imagine it will be a mixture of the ideology of the PUP--without the paramilitary connection--and Alliance, something that will appeal to both working-class and middle-class unionists and pro-Union Catholics.