lulzbot minis are very expensive for what is basically a small volume single extruder standard printer.
Your best bet to start with would be a replicator pro clone. Either flashforge or qidi.
Has enclosed print volume and dual extruders. So can print with nylons and other material that need heated print volume, plus you can use soluble support materials. And they cost from $600-900
Lulzbot mini is an open frame single extruder with smaller print volume for around $1500.

On the hyrel - davo didn't mention it but it can be used with up to 4 extruders at once. Not sure if you could use 4 materials for one print - but davo will know. Can't think of any reason why not.
And you can use a syringe type head to print silicone as well.