My first Dollfie Dream boy (unboxing)

Aw congratulations! He has such a sweet face

There are people more expert than me, but I had vinyl dolls for quite a few years who made it out without staining. You should assume that dark and bright fabrics and other materials will stain and use caution. If you want him to wear a company made outfit that has dark materials which can touch the vinyl you can put a flesh colored body suit on first. Faux leather is basically another plastic and that material can stain vinyl so so so badly and quickly. Use socks and bodysuits and whatever it takes to make a barrier between materials like that and the vinyl.
Prewashing fabrics before sewing, cotton fabric, and washing outfits can help reduce staining, so that's a good idea if you are dealing with something washable. (Not everything is).
You can probably get more expert hacks in the DD discussion thread if any of those nice people will chime in.
I hope you have a ton of fun with him!

 

I won't claim I am an expert - I've never owned a vinyl doll for an extended period of time. But I can tell you my knowledge from when I dabbled in it. The vinyl world is dominated by Volks and Obitsu. Manufacturing vinyl requires a more complicated industrial process than casting resin, so it's hard for small artists to be able to sell their sculpts in the same way we are used to in the resin world.

Staining

Volks sells "stain prevention suits" on their website which are skin-colored, form fitting bodysuits to prevent clothing from touching the vinyl directly. You'll want the DDS size in Flesh for Alphinaud.

Small stains can will happen even with careful handling and use of bodysuits. A lot of people apply acne cream to the stain to fade marks. The ingredient which makes this work is Benzoyl Peroxide - the brand doesn't matter as long as the acne cream contains this ingredient. Alternatively, Volks sells a cream called "Dream Rescue" which does the same thing.

Dark clothes present the biggest and most obvious stain risk, but anything which is a bright/saturated color can slowly stain the vinyl over time, including wigs (both the hair fibre, and the wig cap if it's dark colored).

If you want more information about staining, I highly recommend you visit DollDreaming, a forum dedicated to vinyl dolls.

Heads

All heads for DD are anime style (the Nier & Final Fantasy collabs are very much an exception) and the vast majority are designed to be female.

Then there is Dream Choice - which is an in person, made-to-order system kind of like Volks Full Choice for their resin dolls. All normal and Dream Choice heads are referred to by numbers starting with DDH (Dollfie Dream Head). Like character heads, you can often buy Dream Choice heads secondhand if you don't want to go through the process of buying a whole doll.

The few male head molds are Dream Choice exclusive. DDH-25 and DDH-26 are specifically designed to be male heads. DDH-16 is androgynous, but also popular as a boy.

Finally, there are the normal/basic heads which can be purchased straight from the Volks website without any extra steps. Of these, DDH-07 is probably the most popular "boy/male" option.

Other vinyl brands who produce heads that can fit DD are Visuadoll (who have a more resin-like aesthetic), and Obitsu (which is very anime). Obitsu have different neck mechanisms to Volks so you'll need to do a little modding to make it work.

Of course, there's also Smart Doll who have occasionally released male dolls, and their heads are perfectly compatible with DD (no modding needed).