Before the Second Vatican Council there was a separation between choir monks (those who are Ordained) and lay monks. Lay monks prayed the Divine Office in the vernacular, only prayed part of it (probably only Lauds, Vespers, and Compline, but I’m sure it varied), and focused on manual labor. However, the choir monks focused on priestly studies, education, and tending to nearby parishes. There was even a physical separation between the lay and choir monks, with them each having their own set of tables in the refectory, and usually not allowing them to intermix for long periods of time, unless it was for work, confession, etc.
Now days most all of the separation has been done away with, and the only remaining difference is that lay monks usually tend to manual labor, although in a lot of monasteries they are allowed to pursue intellectual pursuits, and if they have the talent, artistic ones are quite common too.
About your SSA, that is not something we can answer, and it is the decision of a specific Diocese or Religious Order to accept you with SSA; there isn’t really a hard and fast rule, and you’ll have to speak with a spiritual director and/or a vocations director about this.
Also, since you are not yet Catholic, you should be focusing on joining the Church, and understanding Her Teachings; it’s wonderful that you are thinking about your Vocation, but just be aware that most Dioceses and Religious Communities (if that is where you end up being called) have a period of 2-6 years that converts must wait after being initiated into the Church to even be considered as a potential member. And because you are a convert, and your view of SSA may have been different before your conversion, they may decide to discount it, but that would be the decision of an individual community.
Finally, I want you to know that you are in my prayers, and that we are in similar situations. I have a slight disability that could bar me from some Religious Orders, I converted to Catholicism when I was 15 (I’m now 17), and I’ve been discerning a call to the Benedictine Order almost since I converted. So I know how frustrating it can be having to wait and not be sure if you’ll be accepted. Just make sure to ask Our Lord to give you the Grace to serve Him in everything you do today, tomorrow, and forever, and if it is His Will, show you your vocation. But if it is not, then be content in waiting, and rejoice because you have been allowed to serve Him in your daily life.