addmultisigaddress creates an address respecting the setting, being unable to generate a specific type of address without also adding it to the wallet seems wrong.

I suppose in the future `addresstype` may be refactored to be wallet-specific, which would leave this non-wallet rpc call without an argument. Perhaps there should just be an optional parameter to set it.
/**
     * populate vCoins with vector of available COutputs.
     */
    void AvailableCoins(std::vector<COutput>& vCoins, bool fOnlySafe=true, const CCoinControl *coinControl = nullptr, const CAmount& nMinimumAmount = 1, const CAmount& nMaximumAmount = MAX_MONEY, const CAmount& nMinimumSumAmount = MAX_MONEY, const uint64_t nMaximumCount = 0, const int nMinDepth = 0, const int nMaxDepth = 9999999) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    /**
     * Return list of available coins and locked coins grouped by non-change output address.
     */
    std::map<CTxDestination, std::vector<COutput>> ListCoins() const;
    /**
     * Find non-change parent output.
     */
    const CTxOut& FindNonChangeParentOutput(const CTransaction& tx, int output) const;
    /**
     * Shuffle and select coins until nTargetValue is reached while avoiding
     * small change; This method is stochastic for some inputs and upon
     * completion the coin set and corresponding actual target value is
     * assembled
     */
    bool SelectCoinsMinConf(const CAmount& nTargetValue, const CoinEligibilityFilter& eligibility_filter, std::vector<COutput> vCoins,
        std::set<CInputCoin>& setCoinsRet, CAmount& nValueRet, const CoinSelectionParams& coin_selection_params, bool& bnb_used) const;
    bool IsSpent(const uint256& hash, unsigned int n) const;
    bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void LockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockAllCoins() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void ListLockedCoins(std::vector<COutPoint>& vOutpts) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    /*
     * Rescan abort properties
     */
    void AbortRescan() { fAbortRescan = true; }