For a Slideshow with transitions, motion effects titles
You could do Worse than
ProShowGold
I dont have the very latest version but my version 2.6 is somewhat weak in the area of control over Audio.
You may need to mix your Audio in
Audacity then use it in your PSG project.
If you want complete control over the Process, Sony Vegas Movie Studio is even more able though it may be OTT and despite its powerful Audio may still prefer that you have an external audio editor.
From experience with personal use though, I have used it to create slideshows where the audio matches perfectly with video.
Otherwise PSG is often all I need
Ive not used it with any ready made animations although it accepts video as well as stills and if the animation is output as a Video it may be posibble
If your needs are modest you may explore something simple as all these programs need a little time to learn them .Sony Vegas certainly does but such time often yields rewards
Otherwise most Video Editing Software will allow you do what you seek with varying degrees of ease
Good Luck