Is it possible to navigate (via HTML tags etc.) between HTML Assets and SmartPDF Assets?

Yes. To link to a SmartPDF asset, use the sample code below.

<a href="nextinteract://open?id=9241&amp;path=pdf/a.pdf#2"> LINK TO PDF </a>

<!-- Copyright (c) 2018 The Interact Technology Group.
THE CODE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
All rights reserved. -->

Where the 9241 is the SmartPDF asset id from SAM. Specifying the page number is possible as shown in the above sample.