This is about boiled wool, along with its common applications.
While if avoiding chain-mail on the head, alternatives exist such as hard-felt with pieces of surface metal. Along with Nuno Felting, acting as a liner material. So as to create a wool to wool marriage, as a hard felt outside, with a Nuno Felt inside for padding. Even though a less elegant answer would be cotton.
This is general information about felt, from a potentially biased place.
Hard felt has an application, while also holding a place in people's cultural identity.
Not all felt, ends up as the Hard Felt, often used in the Bowler Hat. Instead, the Nuno Felting is a process allowing fibers such as Merino Wool, to drape like silk. So felt can be used as armor, with its own group of difficulties. Yet will be study enough against most empty handed strikes.
With one substitute for boiled wool being, velour of the natural version. This velour comes in multiple weights, yet is used for ease of movement and a velvety appearance. So is less restrictive than using Lyons Velvet for a dress, under the chain-mail dress, while supplying the black under the steel.
Yet since a warm and casual appearance is generated by the velour, it is not the dress oriented material, known as jersey. And jersey is not the outerwear for comfort, but would contrast with the chain mail dress resting on it. So jersey cloth is for greater visual appeal.
While I prefer comfort and softness, so for personal use what supports that chain mail would be velour fabric. And greater visual effects, such as a sharper contrast with color would use, Duvetyne. With that Duvetyne being a version of twill fabric, with a velvet like nap on one side. So the denseness of twill fabric, with Duvetyne avoids the comfort level of velour. For preserving my life longer, when the variation of chain mail dress, is made of welded stainless steel.
This is the listing of the version of tweed, that would have the stiffness for formal dresses and suits. And that black version of this Duvetyne will be entirely black, on one side. So it provides more protection for the dress, used with the chain mail dress. With that Duvetyne providing a cape that is black, with its outside being on the side with the nap. Those in motion pictures use this for light control, while it is also listed as, commando cloth.
For this homicidal application, both jersey and velour are not the preferred materials. Instead Duvetyne because of it being a twill, combined with the optical quality provided by the nap, will be better.
A thin light and stretchy material, for tights is known as Milliskin. Also used in the motion picture industry for costuming. By clinging to the body and allowing breathable contact, with enough concealment just like with, costumes for certain people playing the role of superheroes.
With near the body, Coolmax is a trade-name to a specially engineered polyester knitted fabric. And those other brand names exist, but under clothing such as a full slip could benefit from these engineered characteristics. It is not about the brand name, so a competitors fabric could be used.