Conclusion

Group	Betterforms	Orbeon
XForms control	xfControl	xforms-control
Control Type	xf<input-control-name> (xfInput)	xforms-<input-control-name> (xforms-input)

Classes for each implementation

Better Forms

xfControl
xfInput, xfOutput, xfRange, xfSecret, xfSelect1, xfSelectorItem, xfSelect, xfCheckBoxLabel, xfCheckBoxValue, xfTextarea, xfTrigger, xfUpload
xsdBoolean, xsdAnyURI, xsdString, ... 
xfLabel
xfValue
xfReadOnly,xfReadWrite
xfRequired,xfOptional
xfEnabled,xfDisabled
xfValid,xfInvalid
xfIncremental

Orbeon

xforms-control 
xforms-input, xforms-output, xforms-range, xforms-secret, xforms-select1, xforms-deselected, xforms-selected, xforms-select, xforms-textarea, xforms-trigger, xforms-upload
xforms-type-string, xforms-type-date, xforms-type-positiveInteger
xforms-label
xforms-input-input
xforms-readonly
xforms-required, xforms-required-filled 
xforms-invalid, xforms-visited xforms-invalid-visited
xforms-select1-appearance-minimal, xforms-select1-appearance-full, xforms-select1-appearance-compact, xforms-trigger-appearance-full, xforms-trigger-appearance-minimal
xforms-disabled 
xforms-alert-inactive, xforms-alert
xforms-visited
xforms-help
xforms-help-image
xforms-hint
xforms-incremental

XSLTForms

Standard

.xforms-value
.xforms-repeat-item
.xforms-repeat-item-selected
.xforms-enabled  .xforms-disabled
.xforms-required .xforms-optional
.xforms-valid .xforms-invalid
.xforms-readonly .xforms-readwrite

Not (yet) implemented:

out-of-range 
in-range 
value-empty 
value-non-empty

Other:

.xforms-control
.xforms-label
.xforms-appearance
.xforms-appearance-compact
.xforms-appearance-minimal
.xforms-focus
.xforms-dialog

.xforms-input
.xforms-secret
.xforms-[help hint alert required]-icon
.xforms-help
.xforms-hint
.xforms-alert
.xforms-[help hint alert]-value
.xforms-message
.xforms-group xforms-group-content
.xforms-trigger
.xforms-select
.xforms-select1
.xforms-submit
.xforms-output
.xforms-textarea