Hotel = ADA + state building code
Senior Housing = Fair Housing laws + state building code + licensing requirements .

Basics are the same: accessible route to every space etc., but there are lots of details if it is a licensed facility. The point of contention here in CA is how many units need a roll-in shower (and thus waterproof bathroom floor and drain)...best sort it out with the powers that be before you get too far down the line. And make sure your electrical/low voltage consultant knows the fire alarm/panic alarm systems.

Anything special to worry about in the licensing req's?

I would just like to add to Spruce's comment. The number of ADA rooms will be determined by the local municipality's barrier-free sub codes. There are charts which tell you # of accessible rooms and at what room count you start to require roll-in showers. I can only speak for NJ, but their code reads that you need an ADA room for each TYPE of unit, which, depending on your floor plan, may put you in a position where you have more ADA rooms than you are required to have by room count alone. This could pose a problem for a boutique hotel. I would clear that up with the plan reviewer.

If you don't need a roll in shower, i believe you will need either a transfer shower, or bathtub with removable or permanent seats and grab bars. Both with handshower fixtures.

Watch out for thresholds and door widths at balconies, as well. The balcony will count as an area that requires an accessible path of egress, requiring a min. width and max threshold. Make sure you check the active leaf width of a sliding door.

Finally, check the design of a kitchenette, if you include one.