Welcome to the forum. I'm also sending you a Private Message. The are some rules that are unique to your situation that you should be aware of (e.g. D2 and D3 eligibility is measures in full-time semesters not calendar years, did you sign a NLI, were you recruited by other schools, etc.). You can also call the NCAA Eligibility Center directly with specific questions.
How will you get seen if you're not playing? You won't be. You'll have to rely mostly on the people who recruited you out of high school. If you ask your current school for permission to contact other schools (and they grant it), and other schools see you in 2019 summer ball, you could get an offer during the summer.
Yes, you can transfer to juco for the spring semester and play during that spring season. I'm pretty sure that you'll have to stay at that school for 1 calendar year before transferring to a 4 year college, which would put you on the field at your 3rd school in the spring of 2020. Again, there are other rules that you'll need to know about, like min GPA, min credits per semester, etc. So if you're going to transfer to a juco, you should probably do that after completing your current semester.
Regarding a 4-4 transfer, I'm pretty sure that you can transfer to another D2 or D3 without sitting out for a year (assuming your current school releases you, and your grades are in order). That includes transferring after your current semester, or if you transfer during summer 2019.