[ConnorMcLeod]

I think you are wrong with PreThink() (Ham_Think) called from PlayerPreThink (Ham_Player_PreThink)

Reading HLSDK it seems to be :

PlayerPreThink (from client.cpp) I don't know if it's engine forward client_PreThink and fakemeta FM_PlayerPreThink but it sounds like it is correct.

/*
================
PlayerPreThink

Called every frame before physics are run
================
*/
void PlayerPreThink( edict_t *pEntity )
{
    entvars_t *pev = &pEntity->v;
    CBasePlayer *pPlayer = (CBasePlayer *)GET_PRIVATE(pEntity);

    if (pPlayer)
        pPlayer->PreThink( );
}

Then CBasePlayer:reThink from player.cpp (Ham_Player_PreThink)

void CBasePlayer::PreThink(void)
{
    int buttonsChanged = (m_afButtonLast ^ pev->button);    // These buttons have changed this frame
    
    // Debounced button codes for pressed/released
    // UNDONE: Do we need auto-repeat?
    m_afButtonPressed =  buttonsChanged & pev->button;      // The changed ones still down are "pressed"
    m_afButtonReleased = buttonsChanged & (~pev->button);   // The ones not down are "released"

    g_pGameRules->PlayerThink( this );

    if ( g_fGameOver )
        return;         // intermission or finale

    UTIL_MakeVectors(pev->v_angle);             // is this still used?
    
    ItemPreFrame( );
    WaterMove();

    if ( g_pGameRules && g_pGameRules->FAllowFlashlight() )
        m_iHideHUD &= ~HIDEHUD_FLASHLIGHT;
    else
        m_iHideHUD |= HIDEHUD_FLASHLIGHT;


    // JOHN: checks if new client data (for HUD and view control) needs to be sent to the client
    UpdateClientData();

And from that one are called
* g_pGameRules->PlayerThink (CHalfLifeMultiplay :: PlayerThink in multiplayer that is hookable with orpheu module)
* ItemPreFrame
* UpdateClientData


Also, ItemPreFrame is not Ham_Item_PreFrame, it's CBasePlayer::ItemPreFrame (not hookable with hamsandwich) from where m_pActiveItem->ItemPreFrame( ); (Ham_Item_PreFrame) is called.

void CBasePlayer::ItemPreFrame()
{
#if defined( CLIENT_WEAPONS )
    if ( m_flNextAttack > 0 )
#else
    if ( gpGlobals->time < m_flNextAttack )
#endif
	{
		return;
	}

	if (!m_pActiveItem)
		return;

	m_pActiveItem->ItemPreFrame( );
}