<aura:component controller="ltngController"
            implements="forceCommunity:availableForAllPageTypes">
<aura:attribute name="userId" type="String" />
<aura:attribute name="contact" type="Contact"/>
<aura:attribute name="fieldSetName" type="String"/>
<aura:attribute name="fields" type="Object[]"/>
<aura:attribute name="picklistValues" type="Object[]" />

<aura:attribute name="form" type="Aura.Component[]"/>
<aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
<!--HTML and other Lightning components-->
<div class="row">
    <div class="section">
        <div class="cell form">
                  {!v.form}
        </div>
    </div>
</div></aura:component>

createForm2 : function(cmp) {
var fields = cmp.get('v.fields');
var obj = cmp.get('v.contact');
for (var i = 0; i < fields.length; i++) {
    var field = fields[i];

    if (field.type != 'PICKLIST'){
        var picklistValues = cmp.get("v.picklistValues");

       // create the inputSelect component and add to the form component
        $A.createComponent("ui:inputSelect",
            {"aura:id":field.label,"label":field.label,
                "required":field.required,"value":obj[field.fieldpath]
            },
            function(newSelect){
                if (newSelect.isValid()){
                    var form = cmp.get("v.form");
                    form.push(newSelect);
                    cmp.set("v.form",form);
                }
            }
        );

        var options = []; // to hold new options in an array
        for (var j = 0; j < picklistValues.length; j++){
            var pItem = picklistValues[j];

         // picklist field matches current field, create option
            if (pItem.fieldName == field.fieldPath){
                $A.createComponent("ui:inputSelectOption",
                    {"label":pItem.ItemLabel, "text":pItem.ItemValue
                    },
                    function(newOption){
                        if (obj[field.fieldPath] == pItem.ItemValue){
                            newOption.set("v.value",true);
                            options.push(newOption);

                 // using cmp.find("<inputSelect aura:id>") doesn't work!!
                            form[form.length - 1].set("v.body",options);
                 // also tried setting "v.options" - same result

                        form[form.length-1].set("v.value", pItem.ItemValue);
                            cmp.set("v.form",form);
                        } else {
                            newOption.set("v.value",false);
                            options.push(newOption);
                            form[form.length - 1].set("v.body",options);
                            cmp.set("v.form",form);
                        }
                    }
                );
            }
        }
    }
}

<div data-aura-rendered-by="442:0" class="uiInput uiInputSelect uiInput--default uiInput--select" data-aura-class="uiInput uiInputSelect uiInput--default uiInput--select">
<label class="uiLabel-left form-element__label uiLabel" for="9:114;a" data-aura-rendered-by="437:0" data-aura-class="uiLabel">
    <span class="" data-aura-rendered-by="438:0">Gender</span>
    <!--render facet: 440:0-->
    <!--render facet: 441:0-->
</label>
<select class=" select" size="1" aria-describedby="" id="9:114;a" data-aura-rendered-by="14:114;a" data-interactive-lib-uid="4">
    <!--render facet: 15:114;a-->
    <option label="" value="undefined"></option>
    <option label="" value="undefined"></option>
</select>