Blousy shorts will catch a lot of wind and can direct bees up to places no bee should ever go. So some kind of short that is tight fitting, at least at the bottom, is best.
When the pads in my upright bike shorts get ratty, I take out the pads and voila, I have recumbent bike shorts. Other kinds of tight athletic shorts can work well too - rowing shorts, compression type workout shorts, etc.
Shorts with the pads still in them work ok, even if the pad is superfluous.
As for tops, I have both recumbent specific and regular upright bike jerseys. The only difference is the pocket locations. The recumbent tops have pockets on the sides, instead of the back. That said I use my upright bike jerseys on the bents all the time. My bents have narrow seats (as yours does too), and I can still use the two outer pockets for slender items - an energy bar or something like that.
Many folks complain about the sun in their eyes when riding a bent, so you may want to use a helmet with a visor on it, or wear a cycling cap if it's not too warm. I have one old cycling cap that I cut the top out of, so it's like a sweatband with a brim on it now. That works ok.
Padded cycling gloves aren't needed, but some form of hand protection is wise. Glad to see that you are using mountain bike shoes and pedals. Road shoes will slip when you put a leg down at stops and you may end up wiping out or doing a very painful split.
Ok, that's all I have to say about warm weather recumbent cycling gear.