How do I restore photos from a time capsule backup (from an old imac using iphoto and an older OS) to a new macbook air? My old mac will not boot.

I have an older 2011 iMac that will not boot. The OS is still on Lion, I think. I have photos on the machine from older point and shoot cameras, as well as from iphones that have been imported to iphoto. All of this has been backed up to my time capsule, fortunately.

I bought a new macbook air (with a much smaller HD 256 gb vs 1tb) which I have set up already, and did not restore any user settings during the setup process or move anything over yet using migration assistant. I needed something right away and didn't spend the time beforehand to understand the ramifications of doing so. I realize I've created a bit of a mess.

I understand that I need to use migration assistant, and while doing so will be able to select applications to move over. When I updated the OS last night, it converted iPhoto to Photos and I set up my icloud for photos last night. If I go through the process of using migration assistant now to move things over, will the restore work? Will I be able to move photos to the photos app using the icloud? I know I'll likely have some cleanup due to the mess I created, I'm just hoping to get all my data off of time capsule successfully.

Thanks in advance.