Instructions:

Navigate to GTAV/x64v.rpf/models/cdimages/streamedpeds_players.rpf/player_one drag the files in there to have the shirt, shoes and pants.

Or if you want to keep the original files just simple do the same but in the mods folder: GTAV/mods/x64v.rpf/models/cdimages/streamedpeds_players.rpf/player_one.

To get the hat, navigate to GTAV/x64v.rpf/models/cdimages/streamedpedprops.rpf/player_one_p

and that's it, now you have Soos's clothes for Franklin.