Is it possible to forward calls from a Mitel 5505 phone with base unit?
I've checked the manual and it looks like the phone doesn't directly support call forwarding.
Even it isn't possible for users to forward calls, is there a different wireless Mitel phone model that you would recommended?
I don't know this phone in particular, but if it doesn't have forwarding built into it natively, can't you just use the feature access codes? Also remember to verify that the COS of the device is allowed to forward. These phones are designed as hospitality guest phones, so if they are programmed like that it would be common to disable all Call Forwarding in the COS.
As far as a wireless phone, we don't support any hospitality sites with cordless guest phones, but have had great luck with the 5624 WiFi phone and Engenius cordless phones, both SIP and analog versions, and Yealink and Panasonic DECT SIP phones on multiple platforms as well.