oh my, sexy talk.
Honestly, it is all head-canon territory. Whatever you imagine Lavellan to be into, that's probably what he's into. Presumably there's a reason they end up attracted to one another, after all. So you can be as weird or as tame as you like.
Agreed. Personally I see Solas with one foot out of the door for a large part of the relationship, he knows it's not forever but he pretends it is, even if it's only for a while. So he's always a little reserved in terms of sweetness or tender touches (although venhan and my heart is there in buckets) and the only time he lets loose is after Wicked Hearts, where my Ilaria and he have a drunken, fumbling, overall clumsy good time (because, remember, it's been a long time for Solas, I haven't decided how experienced my girl is yet) filled with a lot of laughter and lots of sleep afterward. The world didn't end when he let down his guard, so he starts thinking about giving up his mission until... The Breakup. x)
That's how it goes on in my head anyway. I don't really see the Inquisitor or Solas having a lot of free or private time (I always think of those two nosey nobles in the throne room xD), and when they do it's spent wandering Crestwood's fields (Ilaria loved the flowers), or Solas roaming the Fade in ruins while Ilaria sits beside him and reads all those Arcane/Noblility/Criminal/etc. books she gets training in from the Inquisition perks. x)