General advice for new WP theme developer: best approach to building a slider?

I am learning to develop WordPress themes so that I can produce usable, manageable websites for friends etc. I am now developing my second WordPress theme and would really appreciate some advice or guidance from more experienced theme developers.

A friend has designed the single page theme mockup (for a music studio) that I am currently working on and it contains a couple of image sliders (or carousels). One of the image sliders is for ‘bands in residence’ and has a grid of all the band names below the slider. The site administrator needs to be manage this content i.e. able to upload a photo, band name and url.

I don’t know what the best approach is for adding these sliders.

Questions:
1. What sort of post or ‘content type’ should this information constitute, how would an administrator manage it and how would I query it from the template files? Should this information be uploaded as a post or do I need a plugin to allow management of a new post (or content) type? If so, what are good options here?

2. I have experimented with Metaslider (a preexisting slider plugin) which allows an admin to upload photos and create some kind of ‘slide collection’ with all the info I need. The problem is, whilst the slider looks great, Metaslider plugin doesn’t seem to expose an API I can access within my template files to retrieve more info about these collections (it just instructs you to paste a shortcode <?php echo do_shortcode("[metaslider id=21]"); ?>). I would like access to some kind of API so that I can, for example, display the grid of band names beneath the image slider. Are there other slider plugins people know of that offer more ‘developer side’ flexibility in this regard?

3. Perhaps this could / should all be achieved via the theme customiser API?

Although new to PHP I am an experienced developer so happy (actually prefer) to get stuck in with the technical stuff.

Sorry for the long post. Hope it makes sense. Thank you if you read this far!