My seat is a Prologo Delta Kea, and I have to say it fits me to perfection.
It sort of came with the bike. "Sort of" because Cannondale packed the wrong color seat and bar tape with my bike and when they sent the white replacements, they sent the seat from the next model up. FREE UPGRADE!

I rode my bike with the black seat several times and it was not quite right.
I am blessed that my "sort of stock" seat works and I have not had to shop for the perfect seat. The very thought makes me cringe.

As for shorts, I have three brands. I rank them from Super to OK. 1) Performance, 2) Perl Izumi, 3) SheBeast. I think I may be the only person on this sight who is not thrilled with her SheBeast shorts.

I swear by chamois cream. Some pads can be like sand paper for me. I usually just put it on me and not the shorts.

From reading about this subject, I have come to realize that this is not problem with a one-size-fits-all solution. I hope you have a short and inexpensive learning curve in your quest.