It would look best if the RE3 U.B.C.S unit would keep the original look of the since fancy high tech elite soldiers kinda ruin the original look and vibe.

History of the U.B.C.S:
The U.B.C.S. (Umbrella Biohazard Countermeasure Service) became a critical element of Umbrella's bio-weapons enterprise in the 1990s. Due to the volatile nature of the trade and the secret nature of creatures like the Hunters, only the U.B.C.S. had sufficient training to counter accidental releases. A further benefit they had over typical soldiers was access to medication to assist in resisting exposure to the t-Virus.

Some photos from the RE3 intro:
http://www.imfdb.org/images/7/74/Vlcsnap-2009-10-01-15h10m27s61.jpg
http://www.imfdb.org/images/7/75/Wesker's_Report_(frame_20876).jpg
http://www.imfdb.org/images/c/c0/Wesker's_Report_(frame_20886).jpg
http://www.imfdb.org/images/2/25/Vlcsnap-2009-10-01-15h11m02s88.jpg
http://www.imfdb.org/images/2/26/Vlcsnap-2009-10-01-15h11m11s96.jpg

The U.B.C.S operative would look like this (Just without the green beret hat):

https://vignette.wikia.nocookie.net/residentevil/images/f/f8/MikhailV.jpg/revision/latest?cb=20080813073406


The U.B.C.S squad leader would look like this:
http://projectumbrella.net/files/imagecache/preview/images/1694niko_pose_a3.jpg

Weapons: Colt M4A1 Carbine and SIG Pro SP 2009 (squad leader)
Units loadout: U.B.C.S operator: Colt M4A1 Carbine and U.B.C.S operative squad leader: Colt M4A1 and SIG Pro SP 2009. Getting those to Arma 3 would bring back the old-school zombie vibe.

I hope this idea catches your attention

http://www.imfdb.org/wiki/Resident_Evil_3:_Nemesis
http://residentevil.wikia.com/wiki/Umbrella_Biohazard_Countermeasure_Service